Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Aggregate amortization expense of intangible assets	$ 65	$ 64	$ 68
Estimated aggregate future amortization expense of intangible assets for 2016	67
Estimated aggregate future amortization expense of intangible assets for 2017	67
Estimated aggregate future amortization expense of intangible assets for 2018	67
Estimated aggregate future amortization expense of intangible assets for 2019	67
Estimated aggregate future amortization expense of intangible assets for 2020	$ 67
Lower Limit
Finite-Lived Intangible Assets [Line Items]
Range of amortization life of intangible assets	15 years
Upper Limit
Finite-Lived Intangible Assets [Line Items]
Range of amortization life of intangible assets	30 years