Condensed Consolidating Financial Statements - Statements of Comprehensive Income (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Statement Of Income Captions [Line Items]
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
Eliminations [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	(4,951)	(2,748)	(2,534)
Comprehensive income attributable to Waste Management, Inc.	(4,951)	(2,748)	(2,534)
WM [Member] \| Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	1,955	1,189	762
Comprehensive income attributable to Waste Management, Inc.	1,955	1,189	762
WM Holdings [Member] \| Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	2,469	1,369	1,245
Comprehensive income attributable to Waste Management, Inc.	2,469	1,369	1,245
Non-Guarantor Subsidiaries [Member] \| Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	2,564	1,417	1,129
Less: Comprehensive income (loss) attributable to noncontrolling interests		(2)	(1)
Comprehensive income attributable to Waste Management, Inc.	$ 2,564	$ 1,419	$ 1,130

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e557-108580

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4613674-111683

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4569643-111683

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 55
-Paragraph 4K
-URI http://asc.fasb.org/extlink&oid=84234705&loc=SL4591552-111686

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4569616-111683

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 55
-Paragraph 4K
-URI http://asc.fasb.org/extlink&oid=84234705&loc=SL4591552-111686

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