Reserves For Losses (Details Textuals) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card Member receivables reserves for losses - other	$ (22)	$ (21)
Card Member loans reserves for losses - other	(11)	(2)
Allowance for Card Member Receivables and Reserves, Recoveries of Bad Debts	302	269
Allowance for Card Member Loans, Recoveries of Bad Debts	320	324
Card Member Receivables, net write-offs/TDR	49	14
Card Member Loans, net write-offs/TDR	30	(5)
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	(13)	(6)
Card Member loans reserves for losses - other	(18)	(7)
Other Items [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card Member receivables reserves for losses - other	(9)	(8)
Card Member loans reserves for losses - other	$ 7	$ 11