Significant Credit Concentrations (Details 1) - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Card Member loans and receivables exposure
On-balance sheet	$ 177	$ 170
Individuals [Member]
Card Member loans and receivables exposure
On-balance sheet	123	112
Card Member Loans and Receivables [Member]
Card Member loans and receivables exposure
On-balance sheet	138	127
Unused lines-of-credit	302	273
U.S. [Member] | Card Member Loans and Receivables [Member]
Card Member loans and receivables exposure
On-balance sheet	111	102
Unused lines-of-credit	249	224
Non-U.S. [Member] | Card Member Loans and Receivables [Member]
Card Member loans and receivables exposure
On-balance sheet	27	25
Unused lines-of-credit	$ 53	$ 49