Goodwill and Intangible Assets Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Intangible Assets:
Gross Carrying Amount	$ 3,379		$ 3,415
Accumulated Amortization	(2,574)		(2,474)
Amortization expense	109	108
Amortization Expense, Fiscal Year Maturity [Abstract]
Remaining 2014	260
2015	299
2016	174
2017	42
2018	24
Thereafter	6
Expected future intangible asset amortization	805		941
Customer Lists and User Base
Intangible Assets:
Gross Carrying Amount	1,664		1,653
Accumulated Amortization	(1,258)		(1,213)
Weighted-Average Useful Life (Years)	5 years	5 years
Amortization Expense, Fiscal Year Maturity [Abstract]
Expected future intangible asset amortization	406		440
Trademarks and Trade Names
Intangible Assets:
Gross Carrying Amount	870		780
Accumulated Amortization	(702)		(677)
Weighted-Average Useful Life (Years)	5 years	5 years
Amortization Expense, Fiscal Year Maturity [Abstract]
Expected future intangible asset amortization	168		103
Developed Technology
Intangible Assets:
Gross Carrying Amount	572		554
Accumulated Amortization	(424)		(401)
Weighted-Average Useful Life (Years)	4 years	4 years
Amortization Expense, Fiscal Year Maturity [Abstract]
Expected future intangible asset amortization	148		153
Acquisition Related Intangibles
Intangible Assets:
Gross Carrying Amount			155
Accumulated Amortization
Amortization Expense, Fiscal Year Maturity [Abstract]
Expected future intangible asset amortization			155
All Other
Intangible Assets:
Gross Carrying Amount	273		273
Accumulated Amortization	(190)		(183)
Weighted-Average Useful Life (Years)	4 years	4 years
Amortization Expense, Fiscal Year Maturity [Abstract]
Expected future intangible asset amortization	$ 83		$ 90