Intangible Assets (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Finite-Lived Intangible Assets [Line Items]
Document Period End Date			Sep. 30, 2016
Amortization expense relating to all intangible assets	$ 15	$ 16	$ 48	$ 43
Amortization expense for remainder of the year	16		16
Intangible assets amortization expense, year one	56		56
Intangible assets amortization expense, year two	42		42
Intangible assets amortization expense, year three	39		39
Intangible assets amortization expense, year four	39		39
Intangible assets amortization expense, year five	$ 24		$ 24