Reserves For Losses (Details Textuals) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card Member receivables net write-offs	$ (216)	$ (199)
Allowance for Card Member Receivables, Recoveries of Bad Debts	91	90
Allowance for Card Member Loans, Recoveries of Bad Debts	124	106
Other	11	10
Other	(2)	1
Foreign Currency Translation Adjustments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other	6	6
Other	3	10
Other Items [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other	5	4
Other	(5)	(9)
Troubled Debt Restructuring [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Card Member Receivables, Recoveries of Bad Debts	(4)	2
Allowance for Card Member Loans, Recoveries of Bad Debts	$ (15)	$ (7)