Condensed Consolidating Financial Statements - Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Condensed Income Statements, Captions [Line Items]
Operating revenues	$ 3,739	$ 3,677	$ 7,250	$ 7,117
Costs and expenses	3,024	3,004	5,927	5,886
Income from operations	715	673	1,323	1,231
Other income (expense):
Interest expense, net	(93)	(90)	(184)	(182)
Other, net	(13)	(13)	(19)	(45)
Total other income (expense)	(106)	(103)	(203)	(227)
Income before income taxes	609	570	1,120	1,004
Income tax expense (benefit)	110	209	226	346
Consolidated net income	499	361	894	658
Less: Net loss attributable to noncontrolling interests		(1)	(1)	(2)
Net income attributable to Waste Management, Inc.	499	362	895	660
Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues	(44)		(88)
Costs and expenses	(44)		(88)
Other income (expense):
Equity in earnings of subsidiaries, net of tax	(1,179)	(815)	(2,153)	(1,504)
Total other income (expense)	(1,179)	(815)	(2,153)	(1,504)
Income before income taxes	(1,179)	(815)	(2,153)	(1,504)
Consolidated net income	(1,179)	(815)	(2,153)	(1,504)
Net income attributable to Waste Management, Inc.	(1,179)	(815)	(2,153)	(1,504)
WM [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Costs and expenses	44		88
Income from operations	(44)		(88)
Other income (expense):
Interest expense, net	(78)	(74)	(154)	(148)
Equity in earnings of subsidiaries, net of tax	588	406	1,073	749
Total other income (expense)	510	332	919	601
Income before income taxes	466	332	831	601
Income tax expense (benefit)	(33)	(30)	(64)	(59)
Consolidated net income	499	362	895	660
Net income attributable to Waste Management, Inc.	499	362	895	660
WM Holdings [Member] | Reportable Legal Entities [Member]
Other income (expense):
Interest expense, net	(4)	(5)	(9)	(10)
Equity in earnings of subsidiaries, net of tax	591	409	1,080	755
Total other income (expense)	587	404	1,071	745
Income before income taxes	587	404	1,071	745
Income tax expense (benefit)	(1)	(2)	(2)	(4)
Consolidated net income	588	406	1,073	749
Net income attributable to Waste Management, Inc.	588	406	1,073	749
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues	3,783	3,677	7,338	7,117
Costs and expenses	3,024	3,004	5,927	5,886
Income from operations	759	673	1,411	1,231
Other income (expense):
Interest expense, net	(11)	(11)	(21)	(24)
Other, net	(13)	(13)	(19)	(45)
Total other income (expense)	(24)	(24)	(40)	(69)
Income before income taxes	735	649	1,371	1,162
Income tax expense (benefit)	144	241	292	409
Consolidated net income	591	408	1,079	753
Less: Net loss attributable to noncontrolling interests		(1)	(1)	(2)
Net income attributable to Waste Management, Inc.	$ 591	$ 409	$ 1,080	$ 755