Comprehensive Income (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Comprehensive Income:
Consolidated net income	$ 285	$ 258	$ 731	$ 708
Other comprehensive income (loss), net of taxes:
Unrealized losses resulting from changes in fair value of derivative instruments, net of taxes	(12)	(21)	(25)	(54)
Realized (gains) losses on derivative instruments reclassified into earnings, net of taxes	(18)	10	(9)	10
Unrealized gains (losses) on marketable securities, net of taxes	(3)	1	(4)	1
Foreign currency translation adjustments	(82)	30	(46)	20
Change in funded status of post-retirement benefit obligations, net of taxes	0	0	(2)	(1)
Other comprehensive income (loss)	(115)	20	(86)	(24)
Comprehensive income	170	278	645	684
Comprehensive income attributable to noncontrolling interests	(13)	(14)	(36)	(36)
Comprehensive income attributable to Waste Management, Inc.	157	264	609	648
Components of accumulated other comprehensive income, which is included as a component of Waste Management, Inc. Stockholders' equity
Accumulated unrealized losses on derivative instruments, net of taxes	(67)		(67)		(33)
Accumulated unrealized gains on marketable securities, net of taxes	1		1		5
Foreign currency translation adjustments	215		215		261
Funded status of post-retirement benefit obligations, net of taxes	(5)		(5)		(3)
Total accumulated other comprehensive income	$ 144		$ 144		$ 230