Loans and Accounts Receivable (Details 5) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable Impaired [Line Items]
Average balance of impaired loans	$ 1,134	$ 884	$ 757
Interest income recognized	130	102	81
Global Consumer Services Group [Member] | Card Member Loans [Member]
Financing Receivable Impaired [Line Items]
Average balance of impaired loans	878	699	612
Interest income recognized	109	85	68
Global Consumer Services Group [Member] | Card Member Receivables [Member]
Financing Receivable Impaired [Line Items]
Average balance of impaired loans	33	20	14
Interest income recognized	0	0	0
Global Commercial Services [Member] | Card Member Loans [Member]
Financing Receivable Impaired [Line Items]
Average balance of impaired loans	150	120	103
Interest income recognized	21	17	13
Global Commercial Services [Member] | Card Member Receivables [Member]
Financing Receivable Impaired [Line Items]
Average balance of impaired loans	73	45	28
Interest income recognized	$ 0	$ 0	$ 0