Condensed Consolidating Financial Statements - Statements of Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	$ 278	$ 381
Comprehensive income attributable to Waste Management, Inc.	278	381
Eliminations [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	(861)	(819)
Comprehensive income attributable to Waste Management, Inc.	(861)	(819)
WM [Member] | Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	363	349
Comprehensive income attributable to Waste Management, Inc.	363	349
WM Holdings [Member] | Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	429	406
Comprehensive income attributable to Waste Management, Inc.	429	406
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	347	445
Comprehensive income attributable to Waste Management, Inc.	$ 347	$ 445