Landfill and Environmental Remediation Liabilities - Changes (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Landfill and environmental remediation liabilities
Interest accretion			$ 92	$ 91	$ 89
Landfill [Member]
Landfill and environmental remediation liabilities
Beginning balance, landfill			1,576
Obligations incurred and capitalized			69
Obligations settled			(105)
Interest accretion			92
Revisions in estimates and interest rate assumptions			33
Acquisitions, divestitures and other adjustments			10
Ending balance, landfill			1,675	$ 1,576
Ending balance, environmental remediation			251
Asset retirement obligation revision of estimate increase (decrease) related to annual review			19
Asset retirement obligation revision of estimate increase (decrease) related to enhancements to gas and leachate collection systems			$ 12
Risk-free discount rate of the obligations			2.50%	2.50%	2.25%
Environmental Remediation Liabilities [Member]
Landfill and environmental remediation liabilities
Beginning balance, environmental remediation			$ 246
Obligations settled			(21)
Interest accretion			4
Revisions in estimates and interest rate assumptions			23
Acquisitions, divestitures and other adjustments			(1)
Ending balance, environmental remediation			251	$ 246
San Jacinto Waste Pits [Member]
Landfill and environmental remediation liabilities
Beginning balance, environmental remediation			46
Revisions in estimates and interest rate assumptions	$ 9	$ 42	11	44
Ending balance, environmental remediation			$ 55	$ 46