Goodwill and Acquired Intangibles - Acquired Intangible Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Finite-Lived, Gross Carrying Amount	$ 3,607	$ 3,654
Indefinite Lived, Trademarks, Gross Carrying Amount	887	887
Finite-Lived, Accumulated Amortization	(697)	(448)
Total acquired intangibles	4,494	4,541
Finite-Lived, Net Carrying Amount	2,910	3,206
Indefinite Lived, Trademarks, Net Carrying Amount	887	887
Total acquired intangibles, Net Carrying Amount	3,797	4,093
Customer programs
Finite-Lived Intangible Assets [Line Items]
Finite-Lived, Gross Carrying Amount	3,184	3,184
Finite-Lived, Accumulated Amortization	(503)	(273)
Finite-Lived, Net Carrying Amount	2,681	2,911
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-Lived, Gross Carrying Amount	352	359
Finite-Lived, Accumulated Amortization	(140)	(92)
Finite-Lived, Net Carrying Amount	212	267
Other
Finite-Lived Intangible Assets [Line Items]
Finite-Lived, Gross Carrying Amount	71	111
Finite-Lived, Accumulated Amortization	(54)	(83)
Finite-Lived, Net Carrying Amount	$ 17	$ 28