Acquisitions, Goodwill, and Acquired Intangible Assets Allocation of Aggregate Purchase Price of Acquisitions (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Allocation
Goodwill		$ 3,759		$ 3,319		$ 2,655
Acquired intangibles weighted average amortization period	[1]	3 years 11 months
Minimum
Allocation
Intangible assets, estimated useful life		1 year
Maximum
Allocation
Intangible assets, estimated useful life		10 years
Marketing-related
Allocation
Acquired intangibles weighted average amortization period		4 years 5 months
Contract-based
Allocation
Acquired intangibles weighted average amortization period		2 years 1 month
Technology-based
Allocation
Acquired intangibles weighted average amortization period		3 years 11 months
Customer-related
Allocation
Acquired intangibles weighted average amortization period		3 years 7 months
2014 Acquisitions
Purchase Price
Aggregate purchase price				20
Series of Individually Immaterial Business Acquisitions
Purchase Price
Cash paid, net of cash acquired		$ 599		813
Stock options and restricted stock assumed		5		44
Indemnification holdback		86		5
Aggregate purchase price		690		862		195
Allocation
Goodwill		482		707		103
Intangible assets		230	[2]	230	[3]	$ 83
Property and equipment		4		16
Deferred tax assets		55		64
Other assets acquired		53		34
Deferred tax liabilities		85		88
Other liabilities assumed		49		101
Business acquisition, allocation		$ 690		$ 862
Acquired intangibles weighted average amortization period		5 years		5 years
Series of Individually Immaterial Business Acquisitions | Minimum
Allocation
Intangible assets, estimated useful life		1 year		1 year
Series of Individually Immaterial Business Acquisitions | Maximum
Allocation
Intangible assets, estimated useful life		6 years		5 years
Series of Individually Immaterial Business Acquisitions | Marketing-related
Allocation
Intangible assets		$ 3	[2]	$ 23	[3]
Series of Individually Immaterial Business Acquisitions | Contract-based
Allocation
Intangible assets		1	[2]	1	[3]
Series of Individually Immaterial Business Acquisitions | Technology-based
Allocation
Intangible assets		208	[2]	33	[3]
Series of Individually Immaterial Business Acquisitions | Customer-related
Allocation
Intangible assets		$ 18	[2]	$ 173	[3]

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

[2] Acquired intangible assets have estimated useful lives of between one and six years, with a weighted-average amortization period of five years.

[3] Acquired intangible assets have estimated useful lives of between one and five years, with a weighted-average amortization period of five years.