Acquisitions, Goodwill, and Acquired Intangible Assets Acquired Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended		1 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangibles weighted average life remaining	3 years 183 days	[1]
Acquired Intangibles, Gross	$ 1,534	[1],[2]	1,248	[1],[2]
Accumulated Amortization	(770)	[1],[2]	(603)	[1],[2]
Acquired Intangibles, Net	764	[1]	645	[1]
Marketing-related
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangibles weighted average life remaining	5 years 110 days
Acquired Intangibles, Gross	457	[2]	429	[2]
Accumulated Amortization	(199)	[2]	(156)	[2]
Acquired Intangibles, Net	258		273
Contract-based
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangibles weighted average life remaining	2 years 73 days
Acquired Intangibles, Gross	172	[2]	173	[2]
Accumulated Amortization	(125)	[2]	(110)	[2]
Acquired Intangibles, Net	47		63
Technology- and content-based
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangibles weighted average life remaining	3 years 183 days
Acquired Intangibles, Gross	370	[2]	278	[2]
Accumulated Amortization	(129)	[2]	(74)	[2]
Acquired Intangibles, Net	241		204
Customer-related
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangibles weighted average life remaining	2 years 183 days
Acquired Intangibles, Gross	535	[2]	368	[2]
Accumulated Amortization	(317)	[2]	(263)	[2]
Acquired Intangibles, Net	$ 218		105
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			10 years

[1] Intangible assets have estimated useful lives of between one and 10 years.

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