Acquisitions - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended			9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 So	Sep. 30, 2011	Sep. 30, 2012 Oakleaf [Member]	Sep. 30, 2012 Oakleaf [Member]	Dec. 31, 2011 Oakleaf [Member]	Dec. 31, 2010 Oakleaf [Member]	Jul. 28, 2011 Oakleaf [Member]	Sep. 30, 2012 Oil And Gas [Member]
Business Acquisition [Line Items]
Acquisition cost of acquired entity					$ 432	$ 432	$ 432		$ 432
Cash received in acquisition									4
Operating revenues	3,461	3,522	10,215	9,972	143	438		580
Acquisition-related costs classified as Selling, general and administrative expenses							1
Net losses recognized by acquiree post the acquisition date	214	272	593	695	(4)	(8)
Purchase price allocation to goodwill					328	328	327
Number of geographic segments			4
Total consideration, net of cash acquired, for business acquisition			$ 178	$ 645						$ 94
Number of collection and recycling operations acquired			21