Acquisitions - Schedule of Preliminary Allocation of Purchase Price (Detail) - Southern Waste Systems [Member] $ in Millions	Jan. 08, 2016 USD ($)
Finite-Lived Intangible Assets [Line Items]
Total other intangible assets subject to amortization, Amount	$ 182
Total other intangible assets subject to amortization, Weighted Average Amortization Periods	9 years 6 months
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Total other intangible assets subject to amortization, Amount	$ 160
Total other intangible assets subject to amortization, Weighted Average Amortization Periods	10 years
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Total other intangible assets subject to amortization, Amount	$ 18
Total other intangible assets subject to amortization, Weighted Average Amortization Periods	5 years
Trade Name [Member]
Finite-Lived Intangible Assets [Line Items]
Total other intangible assets subject to amortization, Amount	$ 4
Total other intangible assets subject to amortization, Weighted Average Amortization Periods	10 years