Intangible Assets (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Finite-Lived Intangible Assets [Line Items]
Amortization expense relating to all intangible assets	$ 13	$ 15	$ 44	$ 48
Amortization expense for remainder of the year	13		$ 13
Document Fiscal Year Focus			2019
Intangible assets amortization expense, year one	52		$ 52
Intangible assets amortization expense, year two	39		39
Intangible assets amortization expense, year three	28		28
Intangible assets amortization expense, year four	22		22
Intangible assets amortization expense, year five	$ 19		$ 19