Landfill and Environmental Remediation Liabilities - Changes to Landfill and Environmental Remediation Liabilities (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Environmental Exit Cost [Line Items]
Interest accretion	$ 84	$ 84	$ 82
Revisions in cost estimates and interest rate assumptions	(15)	(30)
Ending balance, environmental remediation	253
Environmental Remediation Liabilities [Member]
Environmental Exit Cost [Line Items]
Obligations incurred and capitalized
Beginning balance, environmental remediation	273	284
Obligations settled	(30)	(37)
Interest accretion	4	6
Revisions in cost estimates and interest rate assumptions	5	23
Acquisitions, divestitures and other adjustments	1	(3)
Ending balance, environmental remediation	253	273
Landfill Liabilities [Member]
Environmental Exit Cost [Line Items]
Beginning balance, landfill	1,292	1,266
Obligations incurred and capitalized	58	49
Obligations settled	(87)	(80)
Interest accretion	84	84
Revisions in cost estimates and interest rate assumptions	(8)	(30)
Acquisitions, divestitures and other adjustments	(1)	3
Ending balance, landfill	$ 1,338	$ 1,292

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

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