Landfill and Environmental Remediation Liabilities - Changes (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Landfill and environmental remediation liabilities
Interest accretion	$ 49	$ 47
Ending balance, environmental remediation	242
Landfill [Member]
Landfill and environmental remediation liabilities
Beginning balance, landfill	1,855
Obligations incurred and capitalized	40
Obligations settled	(47)
Interest accretion	49
Revisions in estimates and interest rate assumptions	27
Acquisitions, divestitures and other adjustments	(2)
Ending balance, landfill	1,922
Asset retirement obligation revision of estimate increase (decrease) related to estimated capping activities	10
Asset retirement obligation, increase (decrease) related to landfill closure	8
Environmental Remediation Liabilities [Member]
Landfill and environmental remediation liabilities
Beginning balance, environmental remediation	240
Obligations settled	(11)
Interest accretion	1
Revisions in estimates and interest rate assumptions	12
Ending balance, environmental remediation	242
Increase (decrease) operating expenses due to change in discount rate	$ 12
Risk-free discount rate of the obligations	0.75%		1.75%