Segment and Related Information (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Reportable segments
Gross Operating Revenues	$ 4,053	$ 3,744	$ 11,487	$ 10,802
Intercompany Operating Revenues	(531)	(509)	(1,515)	(1,474)
Net Operating Revenues	3,522	3,235	9,972	9,328
Income from Operations	543	544	1,476	1,542
Eastern [Member]
Reportable segments
Gross Operating Revenues	822	755	2,326	2,214
Intercompany Operating Revenues	(139)	(132)	(387)	(385)
Net Operating Revenues	683	623	1,939	1,829
Income from Operations	146	138	407	390
Midwest [Member]
Reportable segments
Gross Operating Revenues	847	792	2,403	2,266
Intercompany Operating Revenues	(123)	(119)	(355)	(336)
Net Operating Revenues	724	673	2,048	1,930
Income from Operations	175	149	460	372
Southern [Member]
Reportable segments
Gross Operating Revenues	853	903	2,553	2,602
Intercompany Operating Revenues	(104)	(102)	(307)	(303)
Net Operating Revenues	749	801	2,246	2,299
Income from Operations	194	218	579	624
Western [Member]
Reportable segments
Gross Operating Revenues	841	809	2,456	2,372
Intercompany Operating Revenues	(114)	(113)	(336)	(328)
Net Operating Revenues	727	696	2,120	2,044
Income from Operations	154	146	436	416
Wheelabrator [Member]
Reportable segments
Gross Operating Revenues	228	237	664	660
Intercompany Operating Revenues	(28)	(32)	(89)	(92)
Net Operating Revenues	200	205	575	568
Income from Operations	57	67	112	150
Operating Group Total [Member]
Reportable segments
Gross Operating Revenues	4,053	3,744	11,487	10,802
Intercompany Operating Revenues	(531)	(509)	(1,515)	(1,474)
Net Operating Revenues	3,522	3,235	9,972	9,328
Income from Operations	686	680	1,919	1,859
Corporate and Other [Member]
Reportable segments
Gross Operating Revenues	0	0	0	0
Intercompany Operating Revenues	0	0	0	0
Net Operating Revenues	0	0	0	0
Income from Operations	(143)	(136)	(443)	(317)
Other [Member]
Reportable segments
Gross Operating Revenues	462	248	1,085	688
Intercompany Operating Revenues	(23)	(11)	(41)	(30)
Net Operating Revenues	439	237	1,044	658
Income from Operations	$ (40)	$ (38)	$ (75)	$ (93)