Condensed Consolidating Financial Statements - Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Condensed Income Statements, Captions [Line Items]
Operating revenues	$ 3,696	$ 3,511
Costs and expenses	3,075	2,903
Income from operations	621	608
Other income (expense):
Interest expense, net	(96)	(91)
Other, net	(63)	(6)
Total other income (expense)	(159)	(97)
Income before income taxes	462	511
Income tax expense (benefit)	115	116
Consolidated net income	347	395
Less: Net loss attributable to noncontrolling interests		(1)
Net income attributable to Waste Management, Inc.	347	396
Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues	(46)	(44)
Costs and expenses	(46)	(44)
Other income (expense):
Equity in earnings of subsidiaries, net of tax	(887)	(974)
Total other income (expense)	(887)	(974)
Income before income taxes	(887)	(974)
Consolidated net income	(887)	(974)
Net income attributable to Waste Management, Inc.	(887)	(974)
WM [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Costs and expenses	46	44
Income from operations	(46)	(44)
Other income (expense):
Interest expense, net	(80)	(76)
Equity in earnings of subsidiaries, net of tax	440	485
Total other income (expense)	360	409
Income before income taxes	314	365
Income tax expense (benefit)	(33)	(31)
Consolidated net income	347	396
Net income attributable to Waste Management, Inc.	347	396
WM Holdings [Member] | Reportable Legal Entities [Member]
Other income (expense):
Interest expense, net	(5)	(5)
Equity in earnings of subsidiaries, net of tax	447	489
Other, net	(3)
Total other income (expense)	439	484
Income before income taxes	439	484
Income tax expense (benefit)	(1)	(1)
Consolidated net income	440	485
Net income attributable to Waste Management, Inc.	440	485
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues	3,742	3,555
Costs and expenses	3,075	2,903
Income from operations	667	652
Other income (expense):
Interest expense, net	(11)	(10)
Other, net	(60)	(6)
Total other income (expense)	(71)	(16)
Income before income taxes	596	636
Income tax expense (benefit)	149	148
Consolidated net income	447	488
Less: Net loss attributable to noncontrolling interests		(1)
Net income attributable to Waste Management, Inc.	$ 447	$ 489