Basis of Presentation (Policies)	9 Months Ended
Sep. 30, 2019
Basis of Presentation
Basis of Presentation	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 14. 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.
Revenue Recognition	Revenue Recognition 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 collected or delivered as product. We bill for certain services prior to performance. Such services include, among others, certain commercial and residential contracts and equipment rentals. These advance billings are included in deferred revenues and recognized as revenue in the period service is provided. Substantially all our deferred revenues during the reported periods are realized as revenues within one to three months when the related services are performed. Contract Acquisition Costs Our incremental direct costs of obtaining a contract, which consist primarily of sales incentives, are generally deferred and amortized to selling, general and administrative expense over the estimated life of the relevant customer relationship, ranging from 5 to 13 years. Contract acquisition costs that are paid to the customer are deferred and amortized as a reduction in revenue over the contract life. Our contract acquisition costs are classified as current or noncurrent based on the timing of when we expect to recognize amortization and are included in other assets in our Condensed Consolidated Balance Sheet. As of September 30, 2019 and December 31, 2018, we had $150 million and $145 million, respectively, of deferred contract costs, of which $115 million and $109 million, respectively, was related to deferred sales incentives. During the three and nine months ended September 30, 2019, we amortized $6 million and $17 million of sales incentives to selling, general and administrative expense, and $4 million and $15 million of other contract acquisition costs as a reduction in revenue, respectively. During the three and nine months ended September 30, 2018, we amortized $6 million and $17 million of sales incentives to selling, general and administrative expense, and $8 million and $27 million of other contract acquisition costs as a reduction in revenue, respectively.
Adoption of New Accounting Standard and New Accounting Standard Pending Adoption	Adoption of New Accounting Standard Leases — In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02 associated with lease accounting. There were further amendments, including practical expedients, with the issuance of ASU 2018-01 in January 2018, ASU 2018-11 in July 2018 and ASU 2018-20 in December 2018. On January 1, 2019, we adopted these ASUs using the optional transition method which allows entities to continue to apply historical accounting guidance in the comparative periods presented in the year of adoption. Accordingly, our financial statements for the reported periods after January 1, 2019 are presented under this amended guidance, while prior period amounts are not adjusted and continue to be reported in accordance with historical accounting guidance. We elected to apply the following package of practical expedients on a consistent basis permitting entities not to reassess: (i) whether any expired or existing contracts are or contain a lease; (ii) lease classification for any expired or existing leases and (iii) whether initial direct costs for any expired or existing leases qualify for capitalization under the amended guidance. In addition, we applied (i) the practical expedient for land easements, which allows the Company to not apply the lease standard to certain existing land easements at transition and (ii) the practical expedient to include both the lease and non-lease components as a single component and account for it as a lease. The impact of adopting the amended guidance primarily relates to the recognition of lease assets and lease liabilities on the balance sheet for all leases previously classified as operating leases. We recognized $385 million of right-of-use assets and $385 million of related lease liabilities as of January 1, 2019 for our contracts that are classified as operating leases. Leases with an initial term of 12 months, which are not expected to be renewed beyond one year, are not recorded on the balance sheet and are recognized as lease expense on a straight-line basis over the lease term. Our accounting for financing leases, which were formerly referred to as capital leases, remained substantially unchanged. There were no other material impacts on our consolidated financial statements. See Note 4 for additional information and disclosures related to our adoption of this amended guidance. New Accounting Standard Pending Adoption Financial Instrument Credit Losses — In June 2016, the FASB issued ASU 2016-13 associated with the measurement of credit losses on financial instruments. The amended guidance replaces the current incurred loss impairment methodology of recognizing credit losses when a loss is probable, with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to assess credit loss estimates. The amended guidance is effective for the Company on January 1, 2020. We are assessing the provisions of this amended guidance and evaluating the impact on our consolidated financial statements.
Reclassifications	Reclassifications When necessary, reclassifications have been made to our prior period financial information to conform to the current year presentation and are not material to our consolidated financial statements.

Basis of Presentation (Policies)

9 Months Ended

Sep. 30, 2019

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 14. 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.

Revenue Recognition

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 collected or delivered as product. We bill for certain services prior to performance. Such services include, among others, certain commercial and residential contracts and equipment rentals. These advance billings are included in deferred revenues and recognized as revenue in the period service is provided. Substantially all our deferred revenues during the reported periods are realized as revenues within one to three months when the related services are performed.

Contract Acquisition Costs

Our incremental direct costs of obtaining a contract, which consist primarily of sales incentives, are generally deferred and amortized to selling, general and administrative expense over the estimated life of the relevant customer relationship, ranging from 5 to 13 years. Contract acquisition costs that are paid to the customer are deferred and amortized as a reduction in revenue over the contract life. Our contract acquisition costs are classified as current or noncurrent based on the timing of when we expect to recognize amortization and are included in other assets in our Condensed Consolidated Balance Sheet.

As of September 30, 2019 and December 31, 2018, we had $150 million and $145 million, respectively, of deferred contract costs, of which $115 million and $109 million, respectively, was related to deferred sales incentives. During the three and nine months ended September 30, 2019, we amortized $6 million and $17 million of sales incentives to selling, general and administrative expense, and $4 million and $15 million of other contract acquisition costs as a reduction in revenue, respectively. During the three and nine months ended September 30, 2018, we amortized $6 million and $17 million of sales incentives to selling, general and administrative expense, and $8 million and $27 million of other contract acquisition costs as a reduction in revenue, respectively.

Adoption of New Accounting Standard and New Accounting Standard Pending Adoption

Adoption of New Accounting Standard

Leases — In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02 associated with lease accounting. There were further amendments, including practical expedients, with the issuance of ASU 2018-01 in January 2018, ASU 2018-11 in July 2018 and ASU 2018-20 in December 2018. On January 1, 2019, we adopted these ASUs using the optional transition method which allows entities to continue to apply historical accounting guidance in the comparative periods presented in the year of adoption. Accordingly, our financial statements for the reported periods after January 1, 2019 are presented under this amended guidance, while prior period amounts are not adjusted and continue to be reported in accordance with historical accounting guidance.

We elected to apply the following package of practical expedients on a consistent basis permitting entities not to reassess: (i) whether any expired or existing contracts are or contain a lease; (ii) lease classification for any expired or existing leases and (iii) whether initial direct costs for any expired or existing leases qualify for capitalization under the amended guidance. In addition, we applied (i) the practical expedient for land easements, which allows the Company to not apply the lease standard to certain existing land easements at transition and (ii) the practical expedient to include both the lease and non-lease components as a single component and account for it as a lease.

The impact of adopting the amended guidance primarily relates to the recognition of lease assets and lease liabilities on the balance sheet for all leases previously classified as operating leases. We recognized $385 million of right-of-use assets and $385 million of related lease liabilities as of January 1, 2019 for our contracts that are classified as operating leases. Leases with an initial term of 12 months, which are not expected to be renewed beyond one year, are not recorded on the balance sheet and are recognized as lease expense on a straight-line basis over the lease term. Our accounting for financing leases, which were formerly referred to as capital leases, remained substantially unchanged. There were no other material impacts on our consolidated financial statements. See Note 4 for additional information and disclosures related to our adoption of this amended guidance.

New Accounting Standard Pending Adoption

Financial Instrument Credit Losses — In June 2016, the FASB issued ASU 2016-13 associated with the measurement of credit losses on financial instruments. The amended guidance replaces the current incurred loss impairment methodology of recognizing credit losses when a loss is probable, with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to assess credit loss estimates.

The amended guidance is effective for the Company on January 1, 2020. We are assessing the provisions of this amended guidance and evaluating the 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 and are not material to our consolidated financial statements.