Landfill and Environmental Remediation Liabilities - Changes (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Landfill and environmental remediation liabilities
Interest accretion	$ 71	$ 68
Ending balance, environmental remediation	237
Asset retirement obligation revision of estimate increase (decrease) related to estimated capping activities	$ 11
Risk-free discount rate of the obligations	3.00%		2.50%
Increase (decrease) operating expenses due to change in discount rate	$ (5)
Landfill [Member]
Landfill and environmental remediation liabilities
Beginning balance, landfill	1,675
Obligations incurred and capitalized	62
Obligations settled	(71)
Interest accretion	71
Revisions in estimates and interest rate assumptions	7
Acquisitions, divestitures and other adjustments	9
Ending balance, landfill	1,753
Environmental Remediation Liabilities [Member]
Landfill and environmental remediation liabilities
Beginning balance, environmental remediation	251
Obligations settled	(18)
Interest accretion	4
Revisions in estimates and interest rate assumptions	2
Acquisitions, divestitures and other adjustments	(2)
Ending balance, environmental remediation	237
San Jacinto Waste Pits [Member]
Landfill and environmental remediation liabilities
Beginning balance, environmental remediation	55
Ending balance, environmental remediation	$ 55