Intangible Assets (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Finite-Lived Intangible Assets [Line Items]
Amortization expense relating to all intangible assets	$ 16	$ 9	$ 43	$ 25
Amortization expense for remainder of the year	15		15
Intangible assets amortization expense, year one	57		57
Intangible assets amortization expense, year two	52		52
Intangible assets amortization expense, year three	41		41
Intangible assets amortization expense, year four	40		40
Intangible assets amortization expense, year five	$ 40		$ 40