Goodwill and Intangible Assets Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended			3 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended			3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Mar. 31, 2013 Customer Lists and User Base	Jun. 30, 2014 Customer Lists and User Base	Dec. 31, 2013 Customer Lists and User Base	Mar. 31, 2013 Marketing related	Jun. 30, 2014 Marketing related	Dec. 31, 2013 Marketing related	Mar. 31, 2013 Developed Technology	Jun. 30, 2014 Developed Technology	Dec. 31, 2013 Developed Technology	Dec. 31, 2013 Braintree related(1)	Mar. 31, 2013 All Other	Jun. 30, 2014 All Other	Dec. 31, 2013 All Other
Intangible Assets:
Gross Carrying Amount	$ 3,420		$ 3,420		$ 3,415		$ 1,673	$ 1,653		$ 888	$ 780		$ 585	$ 554	$ 155		$ 274	$ 273
Accumulated Amortization	(2,706)		(2,706)		(2,474)		(1,313)	(1,213)		(747)	(677)		(448)	(401)			(198)	(183)
Weighted-Average Useful Life (Years)						5 years	5 years		5 years	5 years		4 years	4 years			4 years	4 years
Amortization expense	103	108	212	216
Amortization Expense, Fiscal Year Maturity [Abstract]
Remaining 2014	160		160
2015	302		302
2016	178		178
2017	44		44
2018	24		24
Thereafter	6		6
Expected future intangible asset amortization	$ 714		$ 714		$ 941		$ 360	$ 440		$ 141	$ 103		$ 137	$ 153	$ 155		$ 76	$ 90