Condensed Consolidating Financial Statements - Statements of Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	$ 413	$ 478	$ 794	$ 842
Less: Comprehensive income (loss) attributable to noncontrolling interests	1		1	(1)
Comprehensive income attributable to Waste Management, Inc.	412	478	793	843
Eliminations [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	(1,075)	(1,179)	(1,962)	(2,153)
Comprehensive income attributable to Waste Management, Inc.	(1,075)	(1,179)	(1,962)	(2,153)
WM [Member] | Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	383	501	732	899
Comprehensive income attributable to Waste Management, Inc.	383	501	732	899
WM Holdings [Member] | Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	530	588	970	1,073
Comprehensive income attributable to Waste Management, Inc.	530	588	970	1,073
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Comprehensive income	575	568	1,054	1,023
Less: Comprehensive income (loss) attributable to noncontrolling interests	1		1	(1)
Comprehensive income attributable to Waste Management, Inc.	$ 574	$ 568	$ 1,053	$ 1,024