Reserves For Losses (Details Textuals) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Card member loans, recoveries of bad debts	$ 525,000,000	$ 444,000,000	$ 409,000,000
Card member loans, recoveries of bad debts - TDR	(79,000,000)	(33,000,000)	(30,000,000)
Card member receivables, recoveries of bad debts	374,000,000	367,000,000	366,000,000
Card member receivables, recoveries of bad debts - TDR	(16,000,000)	0	2,000,000
Foreign Currency Translation Adjustments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net write-offs	4,000,000	(11,000,000)	8,000,000
Card Member receivable reserves for losses - Other	0	(6,000,000)	12,000,000
Other Items [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net write-offs	18,000,000	16,000,000	15,000,000
Card Member receivable reserves for losses - Other	$ 17,000,000	$ 20,000,000	$ 17,000,000