Reserves For Losses (Details Textuals) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card Member receivables reserves for losses - other	$ (14)	$ (12)
Card Member loans reserves for losses - other	(2)	(2)
Allowance for Card Member Receivables and Reserves, Recoveries of Bad Debts	201	180
Allowance for Card Member Loans, Recoveries of Bad Debts	212	216
Card Member Receivables, net write-offs/TDR	42	8
Card Member Loans, net write-offs/TDR	22	(2)
Unauthorized Transactions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card Member receivables reserves for losses - other		(7)
Card Member loans reserves for losses - other		(6)
Foreign Currency Translation Adjustments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card Member receivables reserves for losses - other	(7)	0
Card Member loans reserves for losses - other	(8)	(1)
Other Items [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card Member receivables reserves for losses - other	(7)	(5)
Card Member loans reserves for losses - other	$ 6	$ 9