Condensed Consolidating Financial Statements - Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Condensed Income Statements, Captions [Line Items]
Operating revenues	$ 3,729	$ 3,696
Costs and expenses	3,156	3,075
Income from operations	573	621
Other income (expense):
Interest expense, net	(112)	(96)
Other, net	(26)	(63)
Total other income (expense)	(138)	(159)
Income before income taxes	435	462
Income tax expense (benefit)	74	115
Consolidated net income	361	347
Net income attributable to Waste Management, Inc.	361	347
Eliminations [Member]
Other income (expense):
Equity in earnings of subsidiaries, net of tax	(861)	(819)
Total other income (expense)	(861)	(819)
Income before income taxes	(861)	(819)
Consolidated net income	(861)	(819)
Net income attributable to Waste Management, Inc.	(861)	(819)
WM [Member] | Reportable Legal Entities [Member]
Other income (expense):
Interest expense, net	(93)	(80)
Equity in earnings of subsidiaries, net of tax	429	406
Total other income (expense)	336	326
Income before income taxes	336	326
Income tax expense (benefit)	(25)	(21)
Consolidated net income	361	347
Net income attributable to Waste Management, Inc.	361	347
WM Holdings [Member] | Reportable Legal Entities [Member]
Other income (expense):
Interest expense, net	(4)	(5)
Equity in earnings of subsidiaries, net of tax	432	413
Other, net		(3)
Total other income (expense)	428	405
Income before income taxes	428	405
Income tax expense (benefit)	(1)	(1)
Consolidated net income	429	406
Net income attributable to Waste Management, Inc.	429	406
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues	3,729	3,696
Costs and expenses	3,156	3,075
Income from operations	573	621
Other income (expense):
Interest expense, net	(15)	(11)
Other, net	(26)	(60)
Total other income (expense)	(41)	(71)
Income before income taxes	532	550
Income tax expense (benefit)	100	137
Consolidated net income	432	413
Net income attributable to Waste Management, Inc.	$ 432	$ 413