Total costs accrued as of the balance sheet date for environmental loss contingencies.

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Changes to Landfill and Environmental Remediation Liabilities (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended			12 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Environmental Remediation Liabilities [Member]	Dec. 31, 2011 Environmental Remediation Liabilities [Member]	Sep. 30, 2012 Landfill Liabilities [Member]	Dec. 31, 2011 Landfill Liabilities [Member]
Environmental Exit Cost [Line Items]
Beginning balance, Landfill					$ 1,292	$ 1,266
Beginning balance, Environmental Remediation			273	284
Obligations incurred and capitalized					43	49
Obligations settled					(58)	(80)
Obligations settled			(19)	(37)
Interest accretion	62	62			62	84
Interest accretion			3	6
Revisions in cost estimates and interest rate assumptions					4	(30)
Revisions in cost estimates and interest rate assumptions			7	23
Acquisitions, divestitures and other adjustments						3
Acquisitions, divestitures and other adjustments				(3)
Ending balance, Landfill					1,343	1,292
Ending balance, Environmental Remediation	$ 264		$ 264	$ 273