Condensed Consolidating Financial Statements - Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Condensed Income Statements, Captions [Line Items]
Operating revenues	$ 3,511	$ 3,440
Costs and expenses	2,903	2,882
Income from operations	608	558
Other income (expense):
Interest expense, net	(91)	(92)
Other, net	(6)	(32)
Total other income (expense)	(97)	(124)
Income before income taxes	511	434
Income tax expense (benefit)	116	137
Consolidated net income	395	297
Less: Net loss attributable to noncontrolling interests	(1)	(1)
Net income attributable to Waste Management, Inc.	396	298
Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues	(44)
Costs and expenses	(44)
Other income (expense):
Equity in earnings of subsidiaries, net of tax	(974)	(689)
Total other income (expense)	(974)	(689)
Income before income taxes	(974)	(689)
Consolidated net income	(974)	(689)
Net income attributable to Waste Management, Inc.	(974)	(689)
WM [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Costs and expenses	44
Income from operations	(44)
Other income (expense):
Interest expense, net	(76)	(74)
Equity in earnings of subsidiaries, net of tax	485	343
Total other income (expense)	409	269
Income before income taxes	365	269
Income tax expense (benefit)	(31)	(29)
Consolidated net income	396	298
Net income attributable to Waste Management, Inc.	396	298
WM Holdings [Member] | Reportable Legal Entities [Member]
Other income (expense):
Interest expense, net	(5)	(5)
Equity in earnings of subsidiaries, net of tax	489	346
Total other income (expense)	484	341
Income before income taxes	484	341
Income tax expense (benefit)	(1)	(2)
Consolidated net income	485	343
Net income attributable to Waste Management, Inc.	485	343
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues	3,555	3,440
Costs and expenses	2,903	2,882
Income from operations	652	558
Other income (expense):
Interest expense, net	(10)	(13)
Other, net	(6)	(32)
Total other income (expense)	(16)	(45)
Income before income taxes	636	513
Income tax expense (benefit)	148	168
Consolidated net income	488	345
Less: Net loss attributable to noncontrolling interests	(1)	(1)
Net income attributable to Waste Management, Inc.	$ 489	$ 346