Loans and Accounts Receivable (Details 5) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Financing Receivable Impaired [Line Items]
Average balance of impaired loans	$ 881	$ 793	$ 862	$ 746
Interest income recognized	26	22	74	60
U S Consumer Services [Member] | Card Member Loans [Member]
Financing Receivable Impaired [Line Items]
Average balance of impaired loans	636	587	626	555
Interest income recognized	17	14	49	38
U S Consumer Services [Member] | Card Member Receivables [Member]
Financing Receivable Impaired [Line Items]
Average balance of impaired loans	20	13	19	13
Interest income recognized	0	0	0	0
International Consumer and Network Services [Member] | Card Member Loans [Member]
Financing Receivable Impaired [Line Items]
Average balance of impaired loans	59	53	56	52
Interest income recognized	4	4	12	12
Global Commercial Services [Member] | Card Member Loans [Member]
Financing Receivable Impaired [Line Items]
Average balance of impaired loans	122	111	119	102
Interest income recognized	5	4	13	10
Global Commercial Services [Member] | Card Member Receivables [Member]
Financing Receivable Impaired [Line Items]
Average balance of impaired loans	44	29	42	24
Interest income recognized	$ 0	$ 0	$ 0	$ 0