Landfill and Environmental Remediation Liabilities - Changes to Landfill and Environmental Remediation Liabilities (Detail) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015
Environmental Exit Cost [Line Items]
Interest accretion	$ 44	$ 43
Ending balance, environmental remediation	213
Landfill [Member]
Environmental Exit Cost [Line Items]
Beginning balance, landfill	1,518
Obligations incurred and capitalized	29
Obligations settled	(40)
Interest accretion	44
Revisions in estimates and interest rate assumptions	1
Acquisitions, divestitures and other adjustments	4
Ending balance, landfill	1,556
Environmental Remediation Liabilities [Member]
Environmental Exit Cost [Line Items]
Beginning balance, environmental remediation	209
Obligations settled	(10)
Interest accretion	2
Revisions in estimates and interest rate assumptions	12
Acquisitions, divestitures and other adjustments	0
Ending balance, environmental remediation	$ 213

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

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