Reserves For Losses (Details Textuals) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2016	Sep. 30, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card Member receivables reserves for losses - other			$ (3)	$ (22)
Card Member loans reserves for losses - other			70	(11)
Allowance for Card Member Receivables and Reserves, Recoveries of Bad Debts			301	302
Allowance for Card Member Loans, Recoveries of Bad Debts			280	320
Allowance for Card Member Receivables, Recoveries of Bad Debts - TDR			16	49
Allowance for Card Member Loans, Recoveries of Bad Debts - TDR			24	30
CardMember loans transferred from HFS to held for investment	$ 0
Unauthorized Transactions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card Member receivables reserves for losses - 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 reserves for losses - other			0	(13)
Card Member loans reserves for losses - other			(3)	(18)
Other Items [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card Member receivables reserves for losses - other			(3)	(9)
Card Member loans reserves for losses - other			$ 6	$ 7
CardMember loans transferred from HFS to held for investment	245	$ 20
CardMember reserves associated with loans held for investments	$ 60	$ 7