Document and Entity Information - USD ($) $ in Billions	12 Months Ended
Document and Entity Information - USD ($) $ in Billions	Dec. 31, 2017	Feb. 08, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Entity Current Reporting Status	Yes
Entity Registrant Name	WASTE MANAGEMENT INC
Entity Central Index Key	0000823768
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		433,673,878
Entity Public Float			$ 32.2
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 22	$ 32
Accounts receivable, net of allowance for doubtful accounts of $17,704 and $24, respectively	1,805	1,700
Other receivables	569	432
Parts and supplies	96	90
Other assets	132	122
Total current assets	2,624	2,376
Property and equipment, net of accumulated depreciation and amortization of $[000] and $17,152, respectively	11,559	10,950
Goodwill	6,247	6,215
Other intangible assets, net	547	591
Restricted trust and escrow accounts	319	105
Investments in unconsolidated entities	269	320
Other assets	264	302
Total assets	21,829	20,859
Current liabilities:
Accounts payable	1,040	799
Accrued liabilities	980	1,085
Deferred revenues	503	493
Current portion of long-term debt	739	417
Total current liabilities	3,262	2,794
Long-term debt, less current portion	8,752	8,893
Deferred income taxes	1,248	1,482
Landfill and environmental remediation liabilities	1,770	1,675
Other liabilities	755	695
Total liabilities	15,787	15,539
Commitments and contingencies
Waste Management, Inc. stockholders' equity:
Common stock, $0.01 par value; 1,500,000,000 shares authorized; 630,282,461 shares issued	6	6
Additional paid-in capital	4,933	4,850
Retained earnings	8,588	7,388
Accumulated other comprehensive income (loss)	8	(80)
Treasury stock at cost, 196,963,558 and 190,966,584 shares, respectively	(7,516)	(6,867)
Total Waste Management, Inc. stockholders' equity	6,019	5,297
Noncontrolling interests	23	23
Total equity	6,042	5,320
Total liabilities and equity	$ 21,829	$ 20,859

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
CONSOLIDATED BALANCE SHEETS
Allowance for doubtful accounts	$ 21	$ 24
Accumulated depreciation and amortization	$ 17,704	$ 17,152
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,500,000,000	1,500,000,000
Common stock, shares issued	630,282,461	630,282,461
Treasury stock, shares	196,963,558	190,966,584

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED STATEMENTS OF OPERATIONS
Operating revenues	$ 14,485	$ 13,609	$ 12,961
Costs and expenses:
Operating	9,021	8,486	8,231
Selling, general and administrative	1,468	1,410	1,343
Depreciation and amortization	1,376	1,301	1,245
Restructuring		4	15
(Income) expense from divestitures, asset impairments and unusual items, net	(16)	112	82
Total costs and expenses	11,849	11,313	10,916
Income from operations	2,636	2,296	2,045
Other income (expense):
Interest expense, net	(363)	(376)	(385)
Loss on early extinguishment of debt	(6)	(4)	(555)
Equity in net losses of unconsolidated entities	(68)	(44)	(38)
Other, net	(8)	(50)	(7)
Total other income (expense)	(445)	(474)	(985)
Income before income taxes	2,191	1,822	1,060
Income tax expense	242	642	308
Consolidated net income	1,949	1,180	752
Less: Net income (loss) attributable to noncontrolling interests		(2)	(1)
Net income attributable to Waste Management, Inc.	$ 1,949	$ 1,182	$ 753
Basic earnings per common share	$ 4.44	$ 2.66	$ 1.66
Diluted earnings per common share	4.41	2.65	1.65
Cash dividends declared per common share	$ 1.70	$ 1.64	$ 1.54

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Consolidated net income	$ 1,949	$ 1,180	$ 752
Derivative instruments, net	7	12	9
Available-for-sale securities, net	2	5	(2)
Foreign currency translation adjustments	76	28	(159)
Post-retirement benefit obligation, net	3	2	2
Other comprehensive income (loss), net of tax	88	47	(150)
Comprehensive income	2,037	1,227	602
Less: Comprehensive income (loss) attributable to noncontrolling interests		(2)	(1)
Comprehensive income attributable to Waste Management, Inc.	$ 2,037	$ 1,229	$ 603

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Consolidated net income	$ 1,949	$ 1,180	$ 752
Adjustments to reconcile consolidated net income to net cash provided by operating activities:
Depreciation and amortization	1,376	1,301	1,245
Deferred income tax expense (benefit)	(251)	73	30
Interest accretion on landfill liabilities	92	91	89
Interest accretion on and discount rate adjustments to environmental remediation liabilities and recovery assets	3		1
Provision for bad debts	43	42	36
Equity-based compensation expense	101	90	72
Net gain on disposal of assets	(20)	(24)	(18)
Expense from divestitures, asset impairments and other, net	43	110	87
Equity in net losses of unconsolidated entities, net of dividends	39	44	42
Loss on early extinguishment of debt	6	4	555
Change in operating assets and liabilities, net of effects of acquisitions and divestitures:
Receivables	(271)	(78)	(178)
Other current assets	(20)	(12)	16
Other assets	4	78	(7)
Accounts payable and accrued liabilities	126	192	(97)
Deferred revenues and other liabilities	(40)	(85)	(97)
Net cash provided by operating activities	3,180	3,006	2,528
Cash flows from investing activities:
Acquisitions of businesses, net of cash acquired	(200)	(611)	(554)
Capital expenditures	(1,509)	(1,339)	(1,233)
Proceeds from divestitures of businesses and other assets (net of cash divested)	99	43	145
Net receipts from restricted trust and escrow accounts	243		51
Other, net	(12)	(25)	(17)
Net cash used in investing activities	(1,379)	(1,932)	(1,608)
Cash flows from financing activities:
New borrowings	1,027	3,057	2,337
Debt repayments	(1,907)	(2,682)	(2,764)
Net commercial paper borrowings	513
Premiums paid on early extinguishment of debt	(8)	(2)	(555)
Common stock repurchase program	(750)	(725)	(600)
Cash dividends	(750)	(726)	(695)
Exercise of common stock options	95	63	77
Tax payments associated with equity-based compensation transactions	(47)	(30)	(15)
Other, net	16	(36)	30
Net cash used in financing activities	(1,811)	(1,081)	(2,185)
Effect of exchange rate changes on cash and cash equivalents			(3)
Decrease in cash and cash equivalents	(10)	(7)	(1,268)
Cash and cash equivalents at beginning of year	32	39	1,307
Cash and cash equivalents at end of year	$ 22	$ 32	$ 39

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Millions	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]	Noncontrolling Interests [Member]	Total
Beginning balance at Dec. 31, 2014	$ 6	$ 4,585	$ 6,888	$ 23	$ (5,636)	$ 23	$ 5,889
Beginning balance, shares at Dec. 31, 2014	630,282				(171,745)
Equity roll forward
Consolidated net income			753			(1)	752
Other comprehensive income (loss), net of tax				(150)			(150)
Cash dividends			(695)				(695)
Equity-based compensation transactions, net of tax		62	(7)		$ 116		171
Equity-based compensation transaction, shares					3,457
Common stock repurchase program		180			$ (780)		$ (600)
Common stock repurchase program, shares					(14,823)		(14,823,000)
Other, net, shares					6
Ending balance at Dec. 31, 2015	$ 6	4,827	6,939	(127)	$ (6,300)	22	$ 5,367
Ending balance, shares at Dec. 31, 2015	630,282				(183,105)
Equity roll forward
Consolidated net income			1,182			(2)	1,180
Other comprehensive income (loss), net of tax				47			47
Cash dividends			(726)				(726)
Equity-based compensation transactions, net of tax		69	(7)		$ 124		186
Equity-based compensation transaction, shares					3,556
Common stock repurchase program		(45)			$ (680)		$ (725)
Common stock repurchase program, shares					(11,241)		(11,241,000)
Other, net		(1)			$ (11)	3	$ (9)
Other, net, shares					(177)
Ending balance at Dec. 31, 2016	$ 6	4,850	7,388	(80)	$ (6,867)	23	5,320
Ending balance, shares at Dec. 31, 2016	630,282				(190,967)
Equity roll forward
Consolidated net income			1,949				1,949
Other comprehensive income (loss), net of tax				88			88
Cash dividends			(750)				(750)
Equity-based compensation transactions, net of tax		38	1		$ 146		185
Equity-based compensation transaction, shares					4,064
Common stock repurchase program		45			$ (795)		$ (750)
Common stock repurchase program, shares					(10,058)		(10,058,000)
Other, net, shares					(3)
Ending balance at Dec. 31, 2017	$ 6	$ 4,933	$ 8,588	$ 8	$ (7,516)	$ 23	$ 6,042
Ending balance, shares at Dec. 31, 2017	630,282				(196,964)

Business	12 Months Ended
Business	Dec. 31, 2017
Basis of Presentation
Business	1. Business The financial statements presented in this report represent the consolidation of Waste Management, Inc., a Delaware corporation; its wholly-owned and majority-owned subsidiaries; and certain variable interest entities for which Waste Management, Inc. or its subsidiaries are the primary beneficiaries as described in Note 18. Waste Management, Inc. is a holding company and all operations are conducted by its subsidiaries. When the terms “the Company,” “we,” “us” or “our” are used in this document, those terms refer to Waste Management, Inc., its consolidated subsidiaries and consolidated variable interest entities. When we use the term “WM,” we are referring only to Waste Management, Inc., the parent holding company. We are North America’s leading provider of comprehensive waste management environmental services. We partner with our residential, commercial, industrial and municipal customers and the communities we serve to manage and reduce waste at each stage from collection to disposal, while recovering valuable resources and creating clean, renewable energy. Our “Solid Waste” business is operated and managed locally by our subsidiaries that focus on distinct geographic areas and provides collection, transfer, disposal, and recycling and resource recovery services. Through our subsidiaries, we are also a leading developer, operator and owner of landfill gas-to-energy facilities in the United States (“U.S.”). We evaluate, oversee and manage the financial performance of our Solid Waste business subsidiaries through our 17 Areas. We also provide additional services that are not managed through our Solid Waste business, which are presented in this report as “Other.” Additional information related to our segments is included in Note 19.

Adoption of New Accounting Standards and Reclassifications

12 Months Ended

Dec. 31, 2017

Adoption of New Accounting Standards and Reclassifications

Adoption of New Accounting Standards and Reclassifications

2. Adoption of New Accounting Standards and Reclassifications

Adoption of New Accounting Standards

Equity-Based Compensation — In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016‑09 associated with equity-based compensation as part of its simplification initiative to reduce the cost and complexity of compliance with U.S. Generally Accepted Accounting Principles (“GAAP”), while maintaining or improving the usefulness of the information provided. This amended guidance was effective for the Company on January 1, 2017 and required the following changes to the presentation of our financial statements:

Excess tax benefits or deficiencies for share-based payments are now recorded as a discrete item in the period shares vest or stock options are exercised as an adjustment to income tax expense or benefit rather than additional paid-in capital. This change was applied prospectively as of January 1, 2017. The Company did not have any excess tax benefits that were not previously recognized as of January 1, 2017. See Note 8 for discussion of the current year impact;

As of January 1, 2017, the calculation of diluted weighted average shares outstanding was changed prospectively to no longer include excess tax benefits as assumed proceeds. This change did not have a material impact on our current year diluted earnings per share;

Cash flows related to excess tax benefits or deficiencies are included in net cash provided by operating activities rather than as a financing activity. The Company adopted this change retrospectively, which resulted in an increase to net cash provided by operating activities and a corresponding increase to net cash used in financing activities of $28 million and $15 million for the years ended December 31, 2016 and 2015, respectively;

Cash paid to taxing authorities when withholding shares from an employee’s vesting or exercise of equity-based compensation awards for tax-withholding purposes is now considered a repurchase of the Company’s equity instruments and is classified as net cash used in financing activities rather than as an operating activity. The Company adopted this change retrospectively, which resulted in an increase to net cash provided by operating activities and a corresponding increase to net cash used in financing activities of $18 million and $15 million for the years ended December 31, 2016 and 2015, respectively; and

The Company elected to continue to estimate forfeitures rather than account for forfeitures as they occur.

Goodwill Impairment Testing — In January 2017, the FASB issued ASU 2017‑04 which simplifies the goodwill impairment test by eliminating Step 2 of the quantitative assessment and should reduce the cost and complexity of evaluating goodwill for impairment. Under the amended guidance, when a quantitative assessment is required, an entity will perform a goodwill impairment test by comparing the estimated fair value of a reporting unit with its carrying amount. An impairment charge will be measured as the amount by which the carrying amount exceeds the reporting unit’s estimated fair value, not to exceed the total amount of recorded goodwill. This amended guidance, effective for the Company on January 1, 2020, permits early adoption. The Company’s early adoption on January 1, 2017 did not have a material impact on our consolidated financial statements.

Reclassifications

When necessary, reclassifications have been made to our prior period financial information to conform to the current year presentation.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2017

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

3. Summary of Significant Accounting Policies

Principles of Consolidation

The accompanying Consolidated Financial Statements include the accounts of WM, its wholly-owned and majority-owned subsidiaries and certain variable interest entities for which we have determined that we are the primary beneficiary. All material intercompany balances and transactions have been eliminated. Investments in unconsolidated entities are accounted for under either the equity method or cost method of accounting, as appropriate.

Estimates and Assumptions

In preparing our financial statements, we make numerous estimates and assumptions that affect the accounting for and recognition and disclosure of assets, liabilities, equity, revenues and expenses. We must make these estimates and assumptions because certain information that we use is dependent on future events, cannot be calculated with precision from available data or simply cannot be calculated. In some cases, these estimates are difficult to determine, and we must exercise significant judgment. In preparing our financial statements, the most difficult, subjective and complex estimates and the assumptions that present the greatest amount of uncertainty relate to our accounting for landfills, environmental remediation liabilities, long-lived asset impairments and reserves associated with our insured and self-insured claims. Each of these items is discussed in additional detail below. Actual results could differ materially from the estimates and assumptions that we use in the preparation of our financial statements.

Cash and Cash Equivalents

Cash in excess of current operating requirements is invested in short-term interest-bearing instruments with maturities of three months or less at the date of purchase and is stated at cost, which approximates market value.

Concentrations of Credit Risk

Financial instruments that potentially subject us to concentrations of credit risk consist primarily of cash and cash equivalents, investments held within our restricted trust and escrow accounts, and accounts receivable. We make efforts to control our exposure to credit risk associated with these instruments by (i) placing our assets and other financial interests with a diverse group of credit-worthy financial institutions; (ii) holding high-quality financial instruments while limiting investments in any one instrument and (iii) maintaining strict policies over credit extension that include credit evaluations, credit limits and monitoring procedures, although generally we do not have collateral requirements for credit extensions. We also control our exposure associated with trade receivables by discontinuing service, to the extent allowable, to non-paying customers. However, our overall credit risk associated with trade receivables is limited due to the large number and diversity of customers we serve. As of December 31, 2017 and 2016, no single customer represented greater than 5% of total accounts receivable.

Accounts and Other Receivables

Our receivables, which are recorded when billed, when services are performed or when cash is advanced, are claims against third parties that will generally be settled in cash. The carrying value of our receivables, net of the allowance for doubtful accounts, represents the estimated net realizable value. We estimate our allowance for doubtful accounts based on historical collection trends; type of customer, such as municipal or commercial; the age of outstanding receivables and existing economic conditions. If events or changes in circumstances indicate that specific receivable balances may be impaired, further consideration is given to the collectability of those balances and the allowance is adjusted accordingly. Past-due receivable balances are written off when our internal collection efforts have been unsuccessful. Also, we recognize interest income on long-term interest-bearing notes receivable as the interest accrues under the terms of the notes. We no longer accrue interest once the notes are deemed uncollectible.

Other receivables, as of December 31, 2017 and 2016, include receivables related to income tax payments in excess of our current income tax obligations of $504 million and $352 million, respectively.

Parts and Supplies

Parts and supplies consist primarily of spare parts, fuel, tires, lubricants and processed recycling materials. Our parts and supplies are stated at the lower of cost, using the average cost method, or market.

Landfill Accounting

Cost Basis of Landfill Assets — We capitalize various costs that we incur to make a landfill ready to accept waste. These costs generally include expenditures for land (including the landfill footprint and required landfill buffer property); permitting; excavation; liner material and installation; landfill leachate collection systems; landfill gas collection systems; environmental monitoring equipment for groundwater and landfill gas; and directly related engineering, capitalized interest, on-site road construction and other capital infrastructure costs. The cost basis of our landfill assets also includes asset retirement costs, which represent estimates of future costs associated with landfill final capping, closure and post-closure activities. These costs are discussed below.

Final Capping, Closure and Post-Closure Costs — Following is a description of our asset retirement activities and our related accounting:

Final Capping — Involves the installation of flexible membrane liners and geosynthetic clay liners, drainage and compacted soil layers and topsoil over areas of a landfill where total airspace capacity has been consumed. Final capping asset retirement obligations are recorded on a units-of-consumption basis as airspace is consumed related to the specific final capping event with a corresponding increase in the landfill asset. Each final capping event is accounted for as a discrete obligation and recorded as an asset and a liability based on estimates of the discounted cash flows and capacity associated with each final capping event.

Closure — Includes the construction of the final portion of methane gas collection systems (when required), demobilization and routine maintenance costs. These are costs incurred after the site ceases to accept waste, but before the landfill is certified as closed by the applicable state regulatory agency. These costs are recorded as an asset retirement obligation as airspace is consumed over the life of the landfill with a corresponding increase in the landfill asset. Closure obligations are recorded over the life of the landfill based on estimates of the discounted cash flows associated with performing closure activities.

Post-Closure — Involves the maintenance and monitoring of a landfill site that has been certified closed by the applicable regulatory agency. Generally, we are required to maintain and monitor landfill sites for a 30-year period. These maintenance and monitoring costs are recorded as an asset retirement obligation as airspace is consumed over the life of the landfill with a corresponding increase in the landfill asset. Post-closure obligations are recorded over the life of the landfill based on estimates of the discounted cash flows associated with performing post-closure activities.

We develop our estimates of these obligations using input from our operations personnel, engineers and accountants. Our estimates are based on our interpretation of current requirements and proposed regulatory changes and are intended to approximate fair value. Absent quoted market prices, the estimate of fair value is based on the best available information, including the results of present value techniques. In many cases, we contract with third parties to fulfill our obligations for final capping, closure and post-closure. We use historical experience, professional engineering judgment and quoted or actual prices paid for similar work to determine the fair value of these obligations. We are required to recognize these obligations at market prices whether we plan to contract with third parties or perform the work ourselves. In those instances where we perform the work with internal resources, the incremental profit margin realized is recognized as a component of operating income when the work is completed.

Once we have determined final capping, closure and post-closure costs, we inflate those costs to the expected time of payment and discount those expected future costs back to present value. During the years ended December 31, 2017, 2016 and 2015, we inflated these costs in current dollars to the expected time of payment using an inflation rate of 2.5%. We discounted these costs to present value using the credit-adjusted, risk-free rate effective at the time an obligation is incurred, consistent with the expected cash flow approach. Any changes in expectations that result in an upward revision to the estimated cash flows are treated as a new liability and discounted at the current rate while downward revisions are discounted at the historical weighted average rate of the recorded obligation. As a result, the credit-adjusted, risk-free discount rate used to calculate the present value of an obligation is specific to each individual asset retirement obligation. The weighted average rate applicable to our long-term asset retirement obligations as of December 31, 2017 was approximately 5.75%.

We record the estimated fair value of final capping, closure and post-closure liabilities for our landfills based on the capacity consumed through the current period. The fair value of final capping obligations is developed based on our estimates of the airspace consumed to date for each final capping event and the expected timing of each final capping event. The fair value of closure and post-closure obligations is developed based on our estimates of the airspace consumed to date for the entire landfill and the expected timing of each closure and post-closure activity. Because these obligations are measured at estimated fair value using present value techniques, changes in the estimated cost or timing of future final capping, closure and post-closure activities could result in a material change in these liabilities, related assets and results of operations. We assess the appropriateness of the estimates used to develop our recorded balances annually, or more often if significant facts change.

Changes in inflation rates or the estimated costs, timing or extent of future final capping, closure and post-closure activities typically result in both (i) a current adjustment to the recorded liability and landfill asset and (ii) a change in liability and asset amounts to be recorded prospectively over either the remaining capacity of the related discrete final capping event or the remaining permitted and expansion airspace (as defined below) of the landfill. Any changes related to the capitalized and future cost of the landfill assets are then recognized in accordance with our amortization policy, which would generally result in amortization expense being recognized prospectively over the remaining capacity of the final capping event or the remaining permitted and expansion airspace of the landfill, as appropriate. Changes in such estimates associated with airspace that has been fully utilized result in an adjustment to the recorded liability and landfill assets with an immediate corresponding adjustment to landfill airspace amortization expense.

Interest accretion on final capping, closure and post-closure liabilities is recorded using the effective interest method and is recorded as final capping, closure and post-closure expense, which is included in operating expenses within our Consolidated Statements of Operations.

Amortization of Landfill Assets — The amortizable basis of a landfill includes (i) amounts previously expended and capitalized; (ii) capitalized landfill final capping, closure and post-closure costs; (iii) projections of future purchase and development costs required to develop the landfill site to its remaining permitted and expansion capacity and (iv) projected asset retirement costs related to landfill final capping, closure and post-closure activities.

Amortization is recorded on a units-of-consumption basis, applying expense as a rate per ton. The rate per ton is calculated by dividing each component of the amortizable basis of a landfill by the number of tons needed to fill the corresponding asset’s airspace. For landfills that we do not own, but operate through lease or other contractual agreements, the rate per ton is calculated based on expected capacity to be utilized over the lesser of the contractual term of the underlying agreement or the life of the landfill.

We apply the following guidelines in determining a landfill’s remaining permitted and expansion airspace:

Remaining Permitted Airspace — Our engineers, in consultation with third-party engineering consultants and surveyors, are responsible for determining remaining permitted airspace at our landfills. The remaining permitted airspace is determined by an annual survey, which is used to compare the existing landfill topography to the expected final landfill topography.

Expansion Airspace — We also include currently unpermitted expansion airspace in our estimate of remaining permitted and expansion airspace in certain circumstances. First, to include airspace associated with an expansion effort, we must generally expect the initial expansion permit application to be submitted within one year and the final expansion permit to be received within five years. Second, we must believe that obtaining the expansion permit is likely, considering the following criteria:

Personnel are actively working on the expansion of an existing landfill, including efforts to obtain land use and local, state or provincial approvals;

We have a legal right to use or obtain land to be included in the expansion plan;

There are no significant known technical, legal, community, business, or political restrictions or similar issues that could negatively affect the success of such expansion; and

Financial analysis has been completed based on conceptual design, and the results demonstrate that the expansion meets Company criteria for investment.

For unpermitted airspace to be initially included in our estimate of remaining permitted and expansion airspace, the expansion effort must meet all of the criteria listed above. These criteria are evaluated by our field-based engineers, accountants, managers and others to identify potential obstacles to obtaining the permits. Once the unpermitted airspace is included, our policy provides that airspace may continue to be included in remaining permitted and expansion airspace even if certain of these criteria are no longer met as long as we continue to believe we will ultimately obtain the permit, based on the facts and circumstances of a specific landfill. In these circumstances, continued inclusion must be approved through a landfill-specific review process that includes approval by our Chief Financial Officer and a review by the Audit Committee of our Board of Directors on a quarterly basis. Of the 15 landfill sites with expansions included as of December 31, 2017, three landfills required the Chief Financial Officer to approve the inclusion of the unpermitted airspace. One landfill required approval by our Chief Financial Officer because of community or political opposition that could impede the expansion process. The remaining two landfills required approval because the permit application process did not meet the one- or five-year requirements.

When we include the expansion airspace in our calculations of remaining permitted and expansion airspace, we also include the projected costs for development, as well as the projected asset retirement costs related to final capping, closure and post-closure of the expansion in the amortization basis of the landfill.

Once the remaining permitted and expansion airspace is determined in cubic yards, an airspace utilization factor (“AUF”) is established to calculate the remaining permitted and expansion capacity in tons. The AUF is established using the measured density obtained from previous annual surveys and is then adjusted to account for future settlement. The amount of settlement that is forecasted will take into account several site-specific factors including current and projected mix of waste type, initial and projected waste density, estimated number of years of life remaining, depth of underlying waste, anticipated access to moisture through precipitation or recirculation of landfill leachate and operating practices. In addition, the initial selection of the AUF is subject to a subsequent multi-level review by our engineering group, and the AUF used is reviewed on a periodic basis and revised as necessary. Our historical experience generally indicates that the impact of settlement at a landfill is greater later in the life of the landfill when the waste placed at the landfill approaches its highest point under the permit requirements.

After determining the costs and remaining permitted and expansion capacity at each of our landfills, we determine the per ton rates that will be expensed as waste is received and deposited at the landfill by dividing the costs by the corresponding number of tons. We calculate per ton amortization rates for each landfill for assets associated with each final capping event, for assets related to closure and post-closure activities and for all other costs capitalized or to be capitalized in the future. These rates per ton are updated annually, or more often, as significant facts change.

It is possible that actual results, including the amount of costs incurred, the timing of final capping, closure and post-closure activities, our airspace utilization or the success of our expansion efforts could ultimately turn out to be significantly different from our estimates and assumptions. To the extent that such estimates, or related assumptions, prove to be significantly different than actual results, lower profitability may be experienced due to higher amortization rates or higher expenses; or higher profitability may result if the opposite occurs. Most significantly, if it is determined that expansion capacity should no longer be considered in calculating the recoverability of a landfill asset, we may be required to recognize an asset impairment or incur significantly higher amortization expense. If at any time management makes the decision to abandon the expansion effort, the capitalized costs related to the expansion effort are expensed immediately.

Environmental Remediation Liabilities

A significant portion of our operating costs and capital expenditures could be characterized as costs of environmental protection. The nature of our operations, particularly with respect to the construction, operation and maintenance of our landfills, subjects us to an array of laws and regulations relating to the protection of the environment. Under current laws and regulations, we may have liabilities for environmental damage caused by our operations, or for damage caused by conditions that existed before we acquired a site. In addition to remediation activity required by state or local authorities, such liabilities include potentially responsible party (“PRP”) investigations. The costs associated with these liabilities can include settlements, certain legal and consultant fees, as well as incremental internal and external costs directly associated with site investigation and clean up.

Where it is probable that a liability has been incurred, we estimate costs required to remediate sites based on site-specific facts and circumstances. We routinely review and evaluate sites that require remediation, considering whether we were an owner, operator, transporter, or generator at the site, the amount and type of waste hauled to the site and the number of years we were associated with the site. Next, we review the same type of information with respect to other named and unnamed PRPs. Estimates of the costs for the likely remedy are then either developed using our internal resources or by third-party environmental engineers or other service providers. Internally developed estimates are based on:

Management’s judgment and experience in remediating our own and unrelated parties’ sites;

Information available from regulatory agencies as to costs of remediation;

The number, financial resources and relative degree of responsibility of other PRPs who may be liable for remediation of a specific site; and

The typical allocation of costs among PRPs, unless the actual allocation has been determined.

Estimating our degree of responsibility for remediation is inherently difficult. We recognize and accrue for an estimated remediation liability when we determine that such liability is both probable and reasonably estimable. Determining the method and ultimate cost of remediation requires that a number of assumptions be made. There can sometimes be a range of reasonable estimates of the costs associated with the likely site remediation alternatives identified in the environmental impact investigation. In these cases, we use the amount within the range that is our best estimate. If no amount within a range appears to be a better estimate than any other, we use the amount that is the low end of such range. If we used the high ends of such ranges, our aggregate potential liability would be approximately $145 million higher than the $251 million recorded in the Consolidated Balance Sheet as of December 31, 2017. Our ultimate responsibility may differ materially from current estimates. It is possible that technological, regulatory or enforcement developments, the results of environmental studies, the inability to identify other PRPs, the inability of other PRPs to contribute to the settlements of such liabilities, or other factors could require us to record additional liabilities. Our ongoing review of our remediation liabilities, in light of relevant internal and external facts and circumstances, could result in revisions to our accruals that could cause upward or downward adjustments to our balance sheet and income from operations. These adjustments could be material in any given period.

Where we believe that both the amount of a particular environmental remediation liability and the timing of the payments are fixed or reliably determinable, we inflate the cost in current dollars (by 2.5% as of December 31, 2017 and 2016) until the expected time of payment and discount the cost to present value using a risk-free discount rate, which is based on the rate for U.S. Treasury bonds with a term approximating the weighted average period until settlement of the underlying obligation. We determine the risk-free discount rate and the inflation rate on an annual basis unless interim changes would materially impact our results of operations. For remedial liabilities that have been discounted, we include interest accretion, based on the effective interest method, in operating expenses in our Consolidated Statements of Operations. The following table summarizes the impacts of revisions in the risk-free discount rate applied to our environmental remediation liabilities and recovery assets for the years ended December 31 (in millions) and the risk-free discount rate applied as of December 31:


	2017			2016			2015
Decrease in operating expenses	$	—		$	(2)		$	(2)
Risk-free discount rate applied to environmental remediation liabilities and recovery assets		2.5	%		2.5	%		2.25	%

The portion of our recorded environmental remediation liabilities that were not subject to inflation or discounting, as the amounts and timing of payments are not fixed or reliably determinable, was $103 million and $90 million as of December 31, 2017 and 2016, respectively. Had we not inflated and discounted any portion of our environmental remediation liability, the amount recorded would have remained the same as of December 31, 2017 and 2016.

Property and Equipment (Exclusive of Landfills, Discussed Above)

We record property and equipment at cost. Expenditures for major additions and improvements are capitalized and maintenance activities are expensed as incurred. We depreciate property and equipment over the estimated useful life of the asset using the straight-line method. We assume no salvage value for our depreciable property and equipment. When property and equipment are retired, sold or otherwise disposed of, the cost and accumulated depreciation are removed from our accounts and any resulting gain or loss is included in results of operations as an offset or increase to operating expense for the period.

The estimated useful lives for significant property and equipment categories are as follows (in years):


		Useful Lives
Vehicles — excluding rail haul cars		3 to 10
Vehicles — rail haul cars		10 to 20
Machinery and equipment — including containers		3 to 30
Buildings and improvements		5 to 40
Furniture, fixtures and office equipment		3 to 10

We include capitalized costs associated with developing or obtaining internal-use software within furniture, fixtures and office equipment. These costs include direct external costs of materials and services used in developing or obtaining the software and internal costs for employees directly associated with the software development project.

Leases

We lease property and equipment in the ordinary course of our business. Our most significant lease obligations are for property and equipment specific to our industry, including real property operated as a landfill or transfer station. Our leases have varying terms. Some may include renewal or purchase options, escalation clauses, restrictions, penalties or other obligations that we consider in determining minimum lease payments. The leases are classified as either operating leases or capital leases, as appropriate.

Operating Leases (Excluding Landfill Leases Discussed Below) — The majority of our leases are operating leases. This classification generally can be attributed to either (i) relatively low fixed minimum lease payments as a result of real property lease obligations that vary based on the volume of waste we receive or process or (ii) minimum lease terms that are much shorter than the assets’ economic useful lives. Management expects that in the normal course of business our operating leases will be renewed, replaced by other leases, or replaced with fixed asset expenditures. Our rent expense during each of the last three years and our future minimum operating lease payments for each of the next five years for which we are contractually obligated as of December 31, 2017 are disclosed in Note 10.

Capital Leases (Excluding Landfill Leases Discussed Below) — Assets under capital leases are capitalized using interest rates determined at the inception of each lease and are amortized over either the useful life of the asset or the lease term, as appropriate, on a straight-line basis. The present value of the related lease payments is recorded as a debt obligation. Our future minimum annual capital lease payments are included in our future debt obligations as disclosed in Note 7.

Landfill Leases — From an operating perspective, landfills that we lease are similar to landfills we own because generally we will operate the landfill for the life of the operating permit. The most significant portion of our rental obligations for landfill leases is contingent upon operating factors such as disposal volumes and often there are no contractual minimum rental obligations. Contingent rental obligations are expensed as incurred. For landfill capital leases that provide for minimum contractual rental obligations, we record the present value of the minimum obligation as part of the landfill asset, which is amortized on a units-of-consumption basis over the shorter of the lease term or the life of the landfill.

Acquisitions

We generally recognize assets acquired and liabilities assumed in business combinations, including contingent assets and liabilities, based on fair value estimates as of the date of acquisition.

Contingent Consideration — In certain acquisitions, we agree to pay additional amounts to sellers contingent upon achievement by the acquired businesses of certain negotiated goals, such as targeted revenue levels, targeted disposal volumes or the issuance of permits for expanded landfill airspace. We have recognized liabilities for these contingent obligations based on their estimated fair value as of the date of acquisition with any differences between the acquisition-date fair value and the ultimate settlement of the obligations being recognized as an adjustment to income from operations.

Acquired Assets and Assumed Liabilities — Assets and liabilities arising from contingencies such as pre-acquisition environmental matters and litigation are recognized at their acquisition-date fair value when their respective fair values can be determined. If the fair values of such contingencies cannot be determined, they are recognized as of the acquisition date if the contingencies are probable and an amount can be reasonably estimated.

Acquisition-date fair value estimates are revised as necessary if, and when, additional information regarding these contingencies becomes available to further define and quantify assets acquired and liabilities assumed. Subsequent to finalization of purchase accounting, these revisions are accounted for as adjustments to income from operations. All acquisition-related transaction costs are expensed as incurred.

Goodwill and Other Intangible Assets

Goodwill is the excess of our purchase cost over the fair value of the net assets of acquired businesses. We do not amortize goodwill, but as discussed in the Long-Lived Asset Impairments section below, we assess our goodwill for impairment at least annually.

Other intangible assets consist primarily of customer and supplier relationships, covenants not-to-compete, licenses, permits (other than landfill permits, as all landfill-related intangible assets are combined with landfill tangible assets and amortized using our landfill amortization policy), and other contracts. Other intangible assets are recorded at fair value on the acquisition date and are generally amortized using either a 150% declining balance approach or a straight-line basis as we determine appropriate. Customer and supplier relationships are typically amortized over a term ranging between 10 and 15 years. Covenants not-to-compete are amortized over the term of the non-compete covenant, which is generally two to five years. Licenses, permits and other contracts are amortized over the definitive terms of the related agreements. If the underlying agreement does not contain definitive terms and the useful life is determined to be indefinite, the asset is not amortized.

Long-Lived Asset Impairments

We assess our long-lived assets for impairment as required under the applicable accounting standards. If necessary, impairments are recorded in (income) expense from divestitures, asset impairments and unusual items, net in our Consolidated Statement of Operations.

Property and Equipment, Including Landfills and Definite-Lived Intangible Assets — We monitor the carrying value of our long-lived assets for potential impairment on an ongoing basis and test the recoverability of such assets generally using significant unobservable (“Level 3”) inputs whenever events or changes in circumstances indicate that their carrying amounts may not be recoverable. These events or changes in circumstances, including management decisions pertaining to such assets, are referred to as impairment indicators. If an impairment indicator occurs, we perform a test of recoverability by comparing the carrying value of the asset or asset group to its undiscounted expected future cash flows. If cash flows cannot be separately and independently identified for a single asset, we will determine whether an impairment has occurred for the group of assets for which we can identify the projected cash flows. If the carrying values are in excess of undiscounted expected future cash flows, we measure any impairment by comparing the fair value of the asset or asset group to its carrying value and the difference is recorded in the period that the impairment indicator occurs. Fair value is generally determined by considering (i) internally developed discounted projected cash flow analysis of the asset or asset group; (ii) actual third-party valuations and/or (iii) information available regarding the current market for similar assets. Estimating future cash flows requires significant judgment and projections may vary from the cash flows eventually realized, which could impact our ability to accurately assess whether an asset has been impaired.

The assessment of impairment indicators and the recoverability of our capitalized costs associated with landfills and related expansion projects require significant judgment due to the unique nature of the waste industry, the highly regulated permitting process and the sensitive estimates involved. During the review of a landfill expansion application, a regulator may initially deny the expansion application although the expansion permit is ultimately granted. In addition, management may periodically divert waste from one landfill to another to conserve remaining permitted landfill airspace, or a landfill may be required to cease accepting waste, prior to receipt of the expansion permit. However, such events occur in the ordinary course of business in the waste industry and do not necessarily result in impairment of our landfill assets because, after consideration of all facts, such events may not affect our belief that we will ultimately obtain the expansion permit. As a result, our tests of recoverability, which generally make use of a probability-weighted cash flow estimation approach, may indicate that no impairment loss should be recorded.

Indefinite-Lived Intangible Assets, Including Goodwill — At least annually, and more frequently if warranted, we assess the indefinite-lived intangible assets including the goodwill of our reporting units for impairment using Level 3 inputs.

We assess whether an impairment exists using a quantitative assessment. Our quantitative assessment identifies potential impairments by comparing the estimated fair value of a reporting unit to its carrying amount, including goodwill. An impairment charge is recognized if the asset’s estimated fair value is less than its carrying amount. Fair value is typically estimated using an income approach. However, when appropriate, we may also use a market approach. The income approach is based on the long-term projected future cash flows of the reporting units. We discount the estimated cash flows to present value using a weighted average cost of capital that considers factors such as market assumptions, the timing of the cash flows and the risks inherent in those cash flows. We believe that this approach is appropriate because it provides a fair value estimate based upon the reporting units’ expected long-term performance considering the economic and market conditions that generally affect our business. The market approach estimates fair value by measuring the aggregate market value of publicly-traded companies with similar characteristics to our business as a multiple of their reported earnings. We then apply that multiple to the reporting units’ earnings to estimate their fair values. We believe that this approach may also be appropriate in certain circumstances because it provides a fair value estimate using valuation inputs from entities with operations and economic characteristics comparable to our reporting units.

Fair value is computed using several factors, including projected future operating results, economic projections, anticipated future cash flows, comparable marketplace data and the cost of capital. There are inherent uncertainties related to these factors and to our judgment in applying them in our analysis. However, we believe our methodology for estimating the fair value of our reporting units is reasonable.

Refer to Note 11 for information related to impairments recognized during the reported periods.

Insured and Self-Insured Claims

We have retained a significant portion of the risks related to our health and welfare, general liability, automobile liability and workers’ compensation claims programs. The exposure for unpaid claims and associated expenses, including incurred but not reported losses, generally is estimated with the assistance of external actuaries and by factoring in pending claims and historical trends and data. The gross estimated liability associated with settling unpaid claims is included in accrued liabilities in our Consolidated Balance Sheets if expected to be settled within one year; otherwise, it is included in long-term other liabilities. Estimated insurance recoveries related to recorded liabilities are reflected as current other receivables or long-term other assets in our Consolidated Balance Sheets when we believe that the receipt of such amounts is probable.

In December 2017, we elected to use a wholly-owned insurance captive to insure the deductibles for our general liability, automobile liability and workers’ compensation claims programs. We continue to maintain conventional insurance policies with third-party insurers. In addition to certain business and operating benefits of having a wholly-owned insurance captive, we expect to receive certain cash flow benefits related to the timing of tax deductions related to these claims. WM will pay an annual premium to the insurance captive, typically in the first quarter of the year comprised of equal parts cash and an intercompany note, for the estimated losses based on the external actuarial analysis. These premiums are held in a restricted escrow account to be used solely for paying insurance claims, resulting in a transfer of risk from WM to the insurance captive.

Restricted Trust and Escrow Accounts

Our restricted trust and escrow accounts consist principally of funds deposited for purposes of funding insurance claims and settling landfill final capping, closure, post-closure and environmental remediation obligations. In December 2017, we elected to use a wholly-owned insurance captive to insure the deductibles for certain claims programs, as discussed above in Insured and Self-Insured Claims, and the premiums paid were directly deposited into a restricted escrow account to be used solely for paying insurance claims. At several of our landfills, we provide financial assurance by depositing cash into restricted trust or escrow accounts for purposes of settling final capping, closure, post-closure and environmental remediation obligations. Balances maintained in these restricted trust and escrow accounts will fluctuate based on (i) changes in statutory requirements; (ii) future deposits made to comply with contractual arrangements; (iii) the ongoing use of funds; (iv) acquisitions or divestitures and (v) changes in the fair value of the financial instruments held in the restricted trust or escrow accounts.

See Note 18 for additional discussion related to restricted trust and escrow accounts for final capping, closure, post-closure or environmental remediation obligations.

Investments in Unconsolidated Entities

Investments in unconsolidated entities over which the Company has significant influence are accounted for under the equity method of accounting. Investments in entities in which the Company does not have the ability to exert significant influence over the investees’ operating and financing activities are accounted for under the cost method of accounting. The following table summarizes our equity and cost method investments as of December 31 (in millions):


	2017		2016
Equity method investments	$	127	$	173
Cost method investments		142		147
Investments in unconsolidated entities	$	269	$	320

We monitor and assess the carrying value of our investments throughout the year for potential impairment and write them down to their fair value when other-than-temporary declines exist. Fair value is generally based on (i) other third-party investors’ recent transactions in the securities; (ii) other information available regarding the current market for similar assets and/or (iii) a market or income approach, as deemed appropriate. Impairments of equity and cost method investments are recorded in equity in net losses of unconsolidated entities and other, net, respectively, in the Consolidated Statements of Operations.

Foreign Currency

We have operations in Canada, as well as certain support functions in India. Local currencies generally are considered the functional currencies of our operations and investments outside the U.S. The assets and liabilities of our foreign operations are translated to U.S. dollars using the exchange rate as of the balance sheet date. Revenues and expenses are translated to U.S. dollars using the average exchange rate during the period. The resulting translation difference is reflected as a component of other comprehensive income (loss).

Cross-Currency Swaps

From time to time, we will use derivative financial instruments to manage our risk associated with fluctuations in foreign currency exchange rates. Through March 2016, we used cross-currency swaps to hedge our exposure to fluctuations in exchange rates for anticipated intercompany cash transactions between Waste Management Holdings, Inc., a wholly-owned subsidiary (“WM Holdings”), and its Canadian subsidiaries.

Our cross-currency swaps had been designated as cash flow hedges for accounting purposes, which resulted in the unrealized changes in the fair value of the derivative instruments being recorded in accumulated other comprehensive income (loss) within our Consolidated Balance Sheets. The associated balance in accumulated other comprehensive income (loss) was reclassified to earnings as the hedged cash flows affected earnings. The financial statement impacts of our cross-currency swaps are discussed in Note 7.

Revenue Recognition

Our revenues are generated from the fees we charge for waste collection, transfer, disposal, and recycling and resource recovery services; from the sale of recycling commodities; from the sale of electricity and landfill gas, which are byproducts of our landfill operations and from the sale of oil and gas. The fees charged for our services are generally defined in our service agreements and vary based on contract-specific terms such as frequency of service, weight, volume and the general market factors influencing a region’s rates. The fees we charge for our services generally include our environmental fee, fuel surcharge and regulatory recovery fee, which are intended to pass through to customers increased direct and indirect costs incurred. We generally recognize revenue as services are performed or products are delivered. For example, revenue typically is recognized as waste is collected, tons are received at our landfills or transfer stations, or recycling commodities are delivered.

We bill for certain services prior to performance. Such services include, among others, certain residential contracts that are billed on a quarterly basis and equipment rentals. These advance billings are included in deferred revenues and recognized as revenue in the period service is provided.

Capitalized Interest

We capitalize interest on certain projects under development, including landfill expansion projects, certain assets under construction, including operating landfills and landfill gas-to-energy projects and internal-use software. During 2017, 2016 and 2015, total interest costs were $383 million, $394 million and $407 million, respectively, of which $15 million, $9 million and $16 million was capitalized in 2017, 2016 and 2015, respectively.

Income Taxes

The Company is subject to income tax in the U.S. and Canada. Current tax obligations associated with our income tax expense are reflected in the accompanying Consolidated Balance Sheets as a component of accrued liabilities and our deferred tax obligations are reflected in deferred income taxes.

Deferred income taxes are based on the difference between the financial reporting and tax basis of assets and liabilities. Deferred income tax expense represents the change during the reporting period in the deferred tax assets and liabilities, net of the effect of acquisitions and dispositions. Deferred tax assets include tax loss and credit carry-forwards and are reduced by a valuation allowance if, based on available evidence, it is more likely than not that some portion or all of the deferred tax assets will not be realized. We establish reserves for uncertain tax positions when, despite our belief that our tax return positions are fully supportable, we believe that certain positions may be challenged and potentially disallowed. When facts and circumstances change, we adjust these reserves through our income tax expense.

Should interest and penalties be assessed by taxing authorities on any underpayment of income tax, such amounts would be accrued and classified as a component of our income tax expense in our Consolidated Statements of Operations.

See Note 8 for discussion of the impacts of enactment of the Tax Cuts and Jobs Act which was signed into law on December 22, 2017 and is generally effective for tax years beginning January 1, 2018.

Contingent Liabilities

We estimate the amount of potential exposure we may have with respect to claims, assessments and litigation in accordance with authoritative guidance on accounting for contingencies. We are party to pending or threatened legal proceedings covering a wide range of matters in various jurisdictions. It is difficult to predict the outcome of litigation, as it is subject to many uncertainties. Additionally, it is not always possible for management to make a meaningful estimate of the potential loss or range of loss associated with such contingencies. See Note 10 for discussion of our commitments and contingencies.

Supplemental Cash Flow Information

The following table shows supplemental cash flow information for the years ended December 31 (in millions):


	2017		2016		2015
Interest, net of capitalized interest	$	380	$	375	$	384
Income taxes		562		442		419

During 2017, we had $452 million of non-cash financing activities due to the initial funding of a wholly-owned insurance captive and tax-exempt bond borrowings. During 2016 and 2015, we did not have any significant non-cash investing and financing activities. Non-cash investing and financing activities are generally excluded from the Consolidated Statements of Cash Flows.

Landfill and Environmental Remediation Liabilities

12 Months Ended

Dec. 31, 2017

Landfill and Environmental Remediation Liabilities

Landfill and Environmental Remediation Liabilities

4. Landfill and Environmental Remediation Liabilities

Liabilities for landfill and environmental remediation costs as of December 31 are presented in the table below (in millions):


	2017						2016
			Environmental						Environmental
	Landfill		Remediation		Total		Landfill		Remediation		Total
Current (in accrued liabilities)	$	128	$	28	$	156	$	119	$	28	$	147
Long-term		1,547		223		1,770		1,457		218		1,675
	$	1,675	$	251	$	1,926	$	1,576	$	246	$	1,822

The changes to landfill and environmental remediation liabilities for the year ended December 31, 2017 are reflected in the table below (in millions):


			Environmental
	Landfill		Remediation
December 31, 2016	$	1,576	$	246
Obligations incurred and capitalized		69		—
Obligations settled		(105)		(21)
Interest accretion		92		4
Revisions in estimates and interest rate assumptions (a) (b)		33		23
Acquisitions, divestitures and other adjustments		10		(1)
December 31, 2017	$	1,675	$	251

(a)

The amount reported for our landfill liabilities includes (i) a net increase of $19 million related to our year-end annual review of landfill final capping, closure and post-closure obligations and (ii) an increase of $12 million primarily for enhancements to our gas and leachate collection systems at certain closed landfills.

(b)

Our environmental remediation liabilities include $11 million of charges to adjust our subsidiary’s estimated potential share of an environmental remediation liability and related costs for a closed site in Harris County, Texas, as discussed in Note 10.

Our recorded liabilities as of December 31, 2017 include the impacts of inflating certain of these costs based on our expectations of the timing of cash settlement and of discounting certain of these costs to present value. Anticipated payments of currently identified environmental remediation liabilities, as measured in current dollars, are $28 million in 2018, $23 million in 2019, $66 million in 2020, $36 million in 2021, $11 million in 2022 and $87 million thereafter.

At several of our landfills, we provide financial assurance by depositing cash into restricted trust funds or escrow accounts for purposes of settling final capping, closure, post-closure and environmental remediation obligations. Generally, these trust funds are established to comply with statutory requirements and operating agreements. See Notes 16 and 18 for additional information related to these trusts.

Property and Equipment

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Property and Equipment

5. Property and Equipment

Property and equipment as of December 31 consisted of the following (in millions):


	2017		2016
Land	$	624	$	608
Landfills		14,904		14,276
Vehicles		4,750		4,433
Machinery and equipment		2,824		2,639
Containers		2,571		2,469
Buildings and improvements		2,846		2,667
Furniture, fixtures and office equipment		744		1,010
		29,263		28,102
Less: Accumulated depreciation of tangible property and equipment		(8,916)		(8,812)
Less: Accumulated amortization of landfill airspace		(8,788)		(8,340)
Property and equipment, net	$	11,559	$	10,950

Depreciation and amortization expense, including amortization expense for assets recorded as capital leases, consisted of the following for the years ended December 31 (in millions):


	2017		2016		2015
Depreciation of tangible property and equipment	$	783	$	773	$	760
Amortization of landfill airspace		497		428		409
Depreciation and amortization expense	$	1,280	$	1,201	$	1,169

Goodwill and Other Intangible Assets

12 Months Ended

Dec. 31, 2017

Goodwill and Other Intangible Assets

Goodwill and Other Intangible Assets

6. Goodwill and Other Intangible Assets

Goodwill was $6,247 million and $6,215 million as of December 31, 2017 and 2016, respectively. The $32 million increase in goodwill during 2017 is primarily related to acquisitions, as well as translation adjustments related to our Canadian operations partially offset by impairment charges.

As discussed more fully in Note 3, we perform our annual impairment test of goodwill balances for our reporting units using a measurement date of October 1. We will also perform interim tests if an impairment indicator exists. As a result of our annual impairment tests, we recorded goodwill impairment charges during the fourth quarter of 2017 of $32 million for a reporting unit in our Energy and Environmental Services (“EES”) organization and $2 million for our LampTracker® reporting unit, as their carrying values including goodwill exceeded estimated fair values. Fair values were estimated using an income approach based on long-term projected discounted future cash flows of the reporting units.

See Notes 11, 17 and 19 for additional information related to goodwill.

Our other intangible assets consisted of the following as of December 31 (in millions):


	Customer		Covenants		Licenses,
	and Supplier		Not-to-		Permits
	Relationships		Compete		and Other		Total
2017
Intangible assets	$	880	$	48	$	124	$	1,052
Less: Accumulated amortization		(422)		(21)		(62)		(505)
	$	458	$	27	$	62	$	547
2016
Intangible assets	$	835	$	59	$	123	$	1,017
Less: Accumulated amortization		(342)		(31)		(53)		(426)
	$	493	$	28	$	70	$	591

Amortization expense for other intangible assets was $96 million, $100 million and $76 million for 2017, 2016 and 2015, respectively. As of December 31, 2017, we had $18 million of licenses, permits and other intangible assets that are not subject to amortization because they do not have stated expirations or have routine, administrative renewal processes. Additional information related to other intangible assets acquired through business combinations is included in Note 17. As of December 31, 2017, we expect annual amortization expense related to other intangible assets to be $94 million in 2018, $83 million in 2019, $74 million in 2020, $62 million in 2021 and $49 million in 2022.

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Debt

12 Months Ended

Dec. 31, 2017

Debt

Debt

7. Debt

The following table summarizes the major components of debt as of each balance sheet date (in millions) and provides the maturities and interest rate ranges of each major category as of December 31:


	2017		2016
$2.25 billion revolving credit facility, maturing July 2020 (weighted average interest rate of 1.9% as of December 31, 2016)	$	—	$	426
Commercial paper program (weighted average interest rate of 1.9% as of December 31, 2017)		515		—
Canadian term loan and revolving credit facility, maturing March 2019 (weighted average effective interest rate of 2.5% as of December 31, 2017 and 2.1% as of December 31, 2016)		113		239
Senior notes, maturing through 2045, interest rates ranging from 2.4% to 7.75% (weighted average interest rate of 4.3% as of December 31, 2017 and 4.6% as of December 31, 2016)		6,184		6,033
Tax-exempt bonds, maturing through 2045, fixed and variable interest rates ranging from 1.2% to 5.7% (weighted average interest rate of 2.0% as of December 31, 2017 and 1.8% as of December 31, 2016)		2,352		2,304
Capital leases and other, maturing through 2055, interest rates up to 12%		327		308
		9,491		9,310
Current portion of long-term debt		739		417
	$	8,752	$	8,893

Debt Classification

As of December 31, 2017, the current portion of our long-term debt balance of $739 million includes (i) $515 million of short-term borrowings under our commercial paper program and (ii) $224 million of other debt with scheduled maturities within the next 12 months, including $167 million of tax-exempt bonds.

We have $831 million of tax-exempt bonds with term interest rate periods that expire within the next 12 months and an additional $328 million of variable-rate tax-exempt bonds that are supported by letters of credit. The interest rates on our variable-rate tax-exempt bonds are generally reset on either a daily or weekly basis through a remarketing process. All recent tax-exempt bond remarketings have successfully placed Company bonds with investors at market-driven rates and we currently expect future remarketings to be successful. However, if the remarketing agent is unable to remarket our bonds, the remarketing agent can put the bonds to us. In the event of a failed remarketing, we have the intent and ability to refinance these bonds on a long-term basis as supported by the forecasted available capacity under our long-term U.S. revolving credit facility (“$2.25 billion revolving credit facility”). Accordingly, we have classified these borrowings as long-term in our Consolidated Balance Sheet as of December 31, 2017.

Access to and Utilization of Credit Facilities and Commercial Paper Program

$2.25 Billion Revolving Credit Facility — Our $2.25 billion revolving credit facility maturing in July 2020 provides us with credit capacity to be used for either cash borrowings or to support letters of credit or commercial paper. The rates we pay for outstanding loans are generally based on LIBOR plus a spread depending on the Company’s debt rating assigned by Moody’s Investors Service and Standard and Poor’s. The spread above LIBOR ranges from 0.805% to 1.3%. As of December 31, 2017, we had no outstanding borrowings under this facility. We had $642 million of letters of credit issued and $515 million of outstanding borrowings under our commercial paper program, both supported by this facility, leaving unused and available credit capacity of $1,093 million as of December 31, 2017.

Commercial Paper Program — We have a $1.5 billion commercial paper program that enables us to borrow funds for up to 397 days at competitive interest rates. The rates we pay for outstanding borrowings are based on the term of the notes. The commercial paper program is fully supported by our $2.25 billion revolving credit facility. As of December 31, 2017, we had $515 million of outstanding borrowings under our commercial paper program.

Canadian Term Loan and Revolving Credit Facility — We have a Canadian credit agreement (which includes a term loan and revolving credit facility) that matures in March 2019. Waste Management of Canada Corporation and WM Quebec Inc., indirect wholly-owned subsidiaries of WM, are borrowers under this agreement. This agreement provides the Company (i) C$50 million of revolving credit capacity, which can be used for borrowings or letters of credit, and (ii) C$460 million of non-revolving term credit that is prepayable without penalty and principal amounts repaid may not be reborrowed. The rates we pay for outstanding loans under the Canadian credit agreement are generally based on the applicable LIBOR plus a spread depending on the Company’s debt rating assigned by Moody’s Investors Service and Standard and Poor’s. The spread above LIBOR ranges from 0.875% to 1.5%. As of December 31, 2017 and 2016, we had C$142 million, or $113 million, and C$321 million, or $239 million, respectively, of outstanding borrowings under our Canadian term loan. As of December 31, 2017 and 2016, we had no borrowings or letters of credit outstanding under the Canadian revolving credit facility.

Other Letter of Credit Facilities — As of December 31, 2017 and 2016, we had utilized $507 million and $492 million, respectively, of other letter of credit facilities, which are both committed and uncommitted, with terms extending through December 2018.

Debt Borrowings and Repayments

$2.25 Billion Revolving Credit Facility — During the year ended December 31, 2017, we had net repayments of $703 million under our $2.25 billion revolving credit facility, including a $277 million repayment of an initial borrowing of $277 million used to fund the insurance premiums for a wholly-owned insurance captive. These borrowings were directly deposited into a restricted escrow account to be used solely for paying insurance claims. Accordingly, the restricted funds provided by these financing activities have not been included in new borrowings in our Consolidated Statement of Cash Flows.

Commercial Paper Program — During the year ended December 31, 2017, we had net cash borrowings of $513 million (net of the related discount on issuance) for general corporate purposes.

Canadian Term Loan — During the year ended December 31, 2017, we repaid C$179 million, or $137 million, of net advances under our Canadian term loan with available cash. The remaining change in the carrying value of outstanding borrowings under our Canadian term loan is due to foreign currency translation.

Senior Notes — In November 2017, we issued $750 million of 3.15% senior notes that mature in November 2027. We utilized the net proceeds of $745 million to repay $590 million of 6.1% senior notes ahead of their scheduled maturity date of March 2018, with the remaining net proceeds used for general corporate purposes. The $6 million loss on early extinguishment of debt reflected in our Consolidated Statement of Operations for the year ended December 31, 2017 relates to this early repayment.

Tax-Exempt Bonds — During the year ended December 31, 2017, we repaid $127 million of our tax-exempt bonds with available cash at their scheduled maturities. In December 2017, we elected to refund and reissue $124 million of tax-exempt bonds in order to reduce the interest costs associated with this debt.

We issued $175 million of tax-exempt bonds in 2017. The proceeds from the issuance of these bonds were deposited directly into a trust fund and may only be used for the specific purpose for which the money was raised, which is generally to finance expenditures for landfill and solid waste disposal facility construction and development. Accordingly, the restricted funds provided by these financing activities have not been included in new borrowings in our Consolidated Statement of Cash Flows.

Capital Leases and Other — During the year ended December 31, 2017, we had $87 million in new capital leases to support new business opportunities, partially offset by net cash repayments of $68 million of other debt.

Scheduled Debt Payments

Principal payments of our debt and capital leases for the next five years and thereafter, based on scheduled maturities are as follows: $737 million in 2018, $302 million in 2019, $754 million in 2020, $549 million in 2021, $592 million in 2022 and $6,667 million thereafter. Our recorded debt and capital lease obligations include non-cash adjustments associated with debt issuance costs, discounts, premiums and fair value adjustments attributable to terminated interest rate derivatives, which have been excluded from these amounts because they will not result in cash payments.

Cross-Currency Swaps

In March 2016, our Canadian subsidiaries repaid C$370 million of intercompany debt to WM Holdings with proceeds from our Canadian term loan. Concurrent with the repayment of the intercompany debt, we terminated the related cross-currency swaps and received $67 million in cash. The cash received from our termination of these swaps was classified as a change in other current assets and other assets within net cash provided by operating activities in the Consolidated Statement of Cash Flows. In addition, we recognized $8 million of expense associated with the termination of these swaps in 2016, which was included in other, net in the Consolidated Statement of Operations.

Senior Notes Refinancing

During 2015, we recognized a pre-tax loss of $552 million associated with the early extinguishment of almost $2 billion of our high-coupon senior notes through make-whole redemption and cash tender offers. We replaced substantially all of the debt extinguished with new senior notes at significantly lower coupon interest rates and extended the weighted average duration of these debt obligations.

Secured Debt

Our debt balances are generally unsecured, except for capital leases and the note payable associated with our investment in low-income housing properties.

Debt Covenants

Our $2.25 billion revolving credit facility, our Canadian credit agreement and certain other financing agreements contain financial covenants. The following table summarizes the most restrictive requirements of these financial covenants (all terms used to measure these ratios are defined by the facilities):


Interest coverage ratio		> 2.75 to 1
Total debt to EBITDA		< 3.50 to 1

Our credit facilities and senior notes also contain certain restrictions intended to monitor our level of subsidiary indebtedness, types of investments and net worth. We monitor our compliance with these restrictions, but do not believe that they significantly impact our ability to enter into investing or financing arrangements typical for our business. As of December 31, 2017 and 2016, we were in compliance with the covenants and restrictions under all of our debt agreements that may have a material effect on our Consolidated Financial Statements.

Income Taxes

12 Months Ended

Dec. 31, 2017

Income Taxes

Income Taxes

8. Income Taxes

Income Tax Expense

Our income tax expense consisted of the following for the years ended December 31 (in millions):


	2017		2016		2015
Current:
Federal	$	400	$	443	$	192
State		56		88		50
Foreign		37		38		36
		493		569		278
Deferred:
Federal		(316)		57		43
State		62		17		(17)
Foreign		3		(1)		4
		(251)		73		30
Income tax expense	$	242	$	642	$	308

The U.S. federal statutory income tax rate is reconciled to the effective income tax rate for the years ended December 31 as follows:


	2017		2016		2015
Income tax expense at U.S. federal statutory rate	35.00	%	35.00	%	35.00	%
State and local income taxes, net of federal income tax benefit	3.25		3.31		3.20
Impacts of enactment of tax reform	(24.14)		—		—
Federal tax credits	(2.31)		(3.08)		(5.49)
Tax impact of equity-based compensation transactions	(1.45)		—		—
Tax impact of impairments	0.66		0.80		0.23
Taxing authority audit settlements and other tax adjustments	0.03		(0.53)		(2.67)
Tax rate differential on foreign income	(0.55)		(0.63)		(0.99)
Other	0.55		0.36		(0.17)
Effective income tax rate	11.04	%	35.23	%	29.11	%

The comparability of our income tax expense for the reported periods has been primarily affected by (i) variations in our income before income taxes; (ii) impacts of enactment of tax reform; (iii) federal tax credits; (iv) excess tax benefits associated with equity-based compensation transactions; (v) the tax implications of impairments; (vi) the realization of state net operating losses and credits; (vii) adjustments to our accruals and related deferred taxes and (viii) tax audit settlements.

For financial reporting purposes, income before income taxes by source for the years ended December 31 was as follows (in millions):


	2017		2016		2015
Domestic	$	2,040	$	1,681	$	922
Foreign