Acquisitions and Divestitures - Allocation of Purchase Price (Detail) - USD ($) $ in Millions	Sep. 30, 2015	Mar. 26, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill	$ 5,886		$ 5,740
Deffenbaugh Disposal, Inc. [Member]
Business Acquisition [Line Items]
Cash and cash equivalents	15	$ 15
Accounts and other receivables	22	18
Parts and supplies	2	2
Deferred income tax asset	11	9
Other current assets	10	12
Property and equipment	207	212
Goodwill	152	140
Other intangible assets	100	134
Other assets	1	1
Accounts payable	(2)	(4)
Accrued liabilities	(15)	(12)
Deferred revenues	(6)	(5)
Landfill and environmental remediation liabilities	(18)	(21)
Deferred income tax liability	(50)	(65)
Other liabilities	(14)	(20)
Total purchase price	415	$ 416
Deffenbaugh Disposal, Inc. [Member] | Adjustments [Member]
Business Acquisition [Line Items]
Accounts and other receivables	4
Deferred income tax asset	2
Other current assets	(2)
Property and equipment	(5)
Goodwill	12
Other intangible assets	(34)
Accounts payable	2
Accrued liabilities	(3)
Deferred revenues	(1)
Landfill and environmental remediation liabilities	3
Deferred income tax liability	15
Other liabilities	6
Total purchase price	$ (1)