Condensed Consolidating Financial Statements - Statements of Comprehensive Income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	$ 1,750	$ 1,833	$ 2,037
Less: Comprehensive income (loss) attributable to noncontrolling interests	1	(2)
Comprehensive income attributable to Waste Management, Inc.	1,749	1,835	2,037
Eliminations [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	(4,055)	(4,324)	(4,951)
Comprehensive income attributable to Waste Management, Inc.	(4,055)	(4,324)	(4,951)
WM [Member] | Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	1,678	1,933	1,955
Comprehensive income attributable to Waste Management, Inc.	1,678	1,933	1,955
WM Holdings [Member] | Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	2,047	2,154	2,469
Comprehensive income attributable to Waste Management, Inc.	2,047	2,154	2,469
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	2,080	2,070	2,564
Less: Comprehensive income (loss) attributable to noncontrolling interests	1	(2)
Comprehensive income attributable to Waste Management, Inc.	$ 2,079	$ 2,072	$ 2,564