Financial Statement Schedule (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Doubtful Accounts, Current [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 106	$ 89	$ 87
Charged/Credited to Net Income	84	249	177
Charged to Other Accounts	0	0	0
Charges Utilized/Write-offs	(88)	(232)	(175)
Balance at End of Period	102	106	89
Allowance for Trasaction, Loan and Interest Losses [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	307	228	193
Charged/Credited to Net Income	968	805	573
Charged to Other Accounts	0	0	0
Charges Utilized/Write-offs	(886)	(726)	(538)
Balance at End of Period	389	307	228
Valuation Allowance of Deferred Tax Assets [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	186	169	83
Charged/Credited to Net Income	(135)	35	16
Charged to Other Accounts	(2)	(2)	78
Charges Utilized/Write-offs	0	(16)	(8)
Balance at End of Period	$ 49	$ 186	$ 169