Condensed Consolidating Statements of Operations (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Condensed Financial Statements, Captions [Line Items]
Operating revenues	$ 3,461	$ 3,522	$ 10,215	$ 9,972
Costs and expenses	2,961	2,979	8,848	8,496
Income from Operations	500	543	1,367	1,476
Other income (expense):
Interest income (expense)	(121)	(117)	(362)	(352)
Other, net	(31)	(5)	(51)	(16)
Total other income (expense)	(152)	(122)	(413)	(368)
Income before income taxes	348	421	954	1,108
Provision for (benefit from) income taxes	125	136	329	377
Consolidated net income	223	285	625	731
Less: Net income attributable to noncontrolling interests	9	13	32	36
Net income attributable to Waste Management, Inc.	214	272	593	695
WM [Member]
Other income (expense):
Interest income (expense)	(91)	(85)	(267)	(256)
Equity in earnings of subsidiaries, net of taxes	269	323	755	850
Total other income (expense)	178	238	488	594
Income before income taxes	178	238	488	594
Provision for (benefit from) income taxes	(36)	(34)	(105)	(101)
Consolidated net income	214	272	593	695
Net income attributable to Waste Management, Inc.	214	272	593	695
WM Holdings [Member]
Other income (expense):
Interest income (expense)	(8)	(8)	(24)	(25)
Equity in earnings of subsidiaries, net of taxes	274	328	770	865
Total other income (expense)	266	320	746	840
Income before income taxes	266	320	746	840
Provision for (benefit from) income taxes	(3)	(3)	(9)	(10)
Consolidated net income	269	323	755	850
Net income attributable to Waste Management, Inc.	269	323	755	850
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Operating revenues	3,461	3,522	10,215	9,972
Costs and expenses	2,961	2,979	8,848	8,496
Income from Operations	500	543	1,367	1,476
Other income (expense):
Interest income (expense)	(22)	(24)	(71)	(71)
Other, net	(31)	(5)	(51)	(16)
Total other income (expense)	(53)	(29)	(122)	(87)
Income before income taxes	447	514	1,245	1,389
Provision for (benefit from) income taxes	164	173	443	488
Consolidated net income	283	341	802	901
Less: Net income attributable to noncontrolling interests	9	13	32	36
Net income attributable to Waste Management, Inc.	274	328	770	865
Eliminations [Member]
Other income (expense):
Equity in earnings of subsidiaries, net of taxes	(543)	(651)	(1,525)	(1,715)
Total other income (expense)	(543)	(651)	(1,525)	(1,715)
Income before income taxes	(543)	(651)	(1,525)	(1,715)
Consolidated net income	(543)	(651)	(1,525)	(1,715)
Net income attributable to Waste Management, Inc.	$ (543)	$ (651)	$ (1,525)	$ (1,715)