Condensed Consolidating Financial Statements - Statements of Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	$ 478	$ 394	$ 842	$ 705
Less: Comprehensive loss attributable to noncontrolling interests		(1)	(1)	(2)
Comprehensive income attributable to Waste Management, Inc.	478	395	843	707
Eliminations [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	(1,179)	(815)	(2,153)	(1,504)
Comprehensive income attributable to Waste Management, Inc.	(1,179)	(815)	(2,153)	(1,504)
WM [Member] \| Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	501	364	899	664
Comprehensive income attributable to Waste Management, Inc.	501	364	899	664
WM Holdings [Member] \| Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	588	406	1,073	749
Comprehensive income attributable to Waste Management, Inc.	588	406	1,073	749
Non-Guarantor Subsidiaries [Member] \| Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	568	439	1,023	796
Less: Comprehensive loss attributable to noncontrolling interests		(1)	(1)	(2)
Comprehensive income attributable to Waste Management, Inc.	$ 568	$ 440	$ 1,024	$ 798

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
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-Section 55
-Paragraph 4K
-URI http://asc.fasb.org/extlink&oid=84234705&loc=SL4591552-111686

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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