Intangible Assets (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Finite-Lived Intangible Assets [Line Items]
Amortization expense relating to all intangible assets	$ 14	$ 19	$ 31	$ 33
Amortization expense for remainder of the year	27		27
Intangible assets amortization expense, year one	51		51
Intangible assets amortization expense, year two	38		38
Intangible assets amortization expense, year three	27		27
Intangible assets amortization expense, year four	23		23
Intangible assets amortization expense, year five	$ 20		$ 20