Intangible Assets (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Finite-Lived Intangible Assets [Line Items]
Amortization expense relating to all intangible assets	$ 9	$ 7	$ 25	$ 20
Amortization expense for remainder of the year	9		9
Intangible assets amortization expense, year one	31		31
Intangible assets amortization expense, year two	31		31
Intangible assets amortization expense, year three	31		31
Intangible assets amortization expense, year four	31		31
Intangible assets amortization expense, year five	$ 31		$ 31