Reserves For Losses (Details Textuals) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2016	Jun. 30, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card Member receivables - other			$ (2,000,000)	$ (14,000,000)
Card Member loans reserves for losses - other			68,000,000	(2,000,000)
Allowance for Card Member Receivables and Reserves, Recoveries of Bad Debts			202,000,000	201,000,000
Allowance for Card Member Loans, Recoveries of Bad Debts			179,000,000	212,000,000
Allowance for Card Member Receivables, Recoveries of Bad Debts - TDR			16,000,000	42,000,000
Allowance for Card Member Loans, Recoveries of Bad Debts - TDR			17,000,000	22,000,000
CardMember loans transferred from HFS to held for investment	$ 245,000,000
Unauthorized Transactions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card Member receivables - other	0
Card Member loans reserves for losses - other	0
Foreign Currency Translation Adjustments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card Member receivables - other			(1,000,000)	(7,000,000)
Card Member loans reserves for losses - other			(2,000,000)	(8,000,000)
Other Items [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card Member receivables - other			(1,000,000)	(7,000,000)
Card Member loans reserves for losses - other			$ 3,000,000	$ 6,000,000
CardMember loans transferred from HFS to held for investment	245,000,000	$ 20,000,000
CardMember reserves associated with loans held for investments	$ 60,000,000	$ 7,000,000