Loans and Accounts Receivable (Details 5) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Financing Receivable, Impaired [Line Items]
Average balance of impaired loans	$ 1,556	$ 1,147	$ 1,466	$ 1,086
Interest income recognized	40	32	116	95
Global Consumer Services Group [Member] | Card Member Loans [Member]
Financing Receivable, Impaired [Line Items]
Average balance of impaired loans	1,170	882	1,113	841
Interest income recognized	34	27	98	79
Global Consumer Services Group [Member] | Card Member Receivables [Member]
Financing Receivable, Impaired [Line Items]
Average balance of impaired loans	58	35	52	31
Interest income recognized	0	0	0	0
Global Commercial Services [Member] | Card Member Loans [Member]
Financing Receivable, Impaired [Line Items]
Average balance of impaired loans	210	153	196	144
Interest income recognized	6	5	18	16
Global Commercial Services [Member] | Card Member Receivables [Member]
Financing Receivable, Impaired [Line Items]
Average balance of impaired loans	118	77	105	70
Interest income recognized	$ 0	$ 0	$ 0	$ 0