Goodwill and Acquired Intangibles - Acquired Intangible Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Finite-lived, gross carrying amount	$ 3,581	$ 3,607
Indefinite lived, trademark, gross carrying amount	887	887
Finite-lived, accumulated amortization	(974)	(697)
Total acquired intangibles	4,468	4,494
Finite-lived, net carrying amount	2,607	2,910
Total acquired intangibles, Net Carrying Amount	3,494	3,797
Customer programs
Finite-Lived Intangible Assets [Line Items]
Finite-lived, gross carrying amount	3,184	3,184
Finite-lived, accumulated amortization	(735)	(503)
Finite-lived, net carrying amount	2,449	2,681
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived, gross carrying amount	344	352
Finite-lived, accumulated amortization	(199)	(140)
Finite-lived, net carrying amount	145	212
Other
Finite-Lived Intangible Assets [Line Items]
Finite-lived, gross carrying amount	53	71
Finite-lived, accumulated amortization	(40)	(54)
Finite-lived, net carrying amount	$ 13	$ 17