Acquisitions, Goodwill, and Acquired Intangible Assets Acquired Intangible Assets (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangibles weighted average life remaining	[1]	4 years 4 months
Acquired Intangibles, Gross	[1],[2]	$ 1,900	$ 1,847
Accumulated Amortization	[1],[2]	(1,046)	(855)
Finite-Lived Intangible Assets, Net	[1],[2]	$ 854	992
Marketing-related
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangibles weighted average life remaining		4 years 7 months
Acquired Intangibles, Gross	[2]	$ 499	502
Accumulated Amortization	[2]	(299)	(252)
Finite-Lived Intangible Assets, Net	[2]	$ 200	250
Contract-based
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangibles weighted average life remaining		4 years 4 months
Acquired Intangibles, Gross	[2]	$ 397	331
Accumulated Amortization	[2]	(212)	(174)
Finite-Lived Intangible Assets, Net	[2]	$ 185	157
Technology-based
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangibles weighted average life remaining		4 years 7 months
Acquired Intangibles, Gross	[2]	$ 705	683
Accumulated Amortization	[2]	(353)	(268)
Finite-Lived Intangible Assets, Net	[2]	$ 352	415
Customer-related
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangibles weighted average life remaining		2 years 8 months
Acquired Intangibles, Gross	[2]	$ 299	331
Accumulated Amortization	[2]	(182)	(161)
Finite-Lived Intangible Assets, Net	[2]	$ 117	$ 170
Minimum
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, estimated useful life		1 year
Maximum
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, estimated useful life		20 years

[1] Intangible assets have estimated useful lives of between one and twenty years.

[2] Excludes the original cost and accumulated amortization of fully-amortized intangibles.