Loans and Accounts Receivable (Details 5) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financing Receivable, Impaired [Line Items]
Average balance of impaired loans	$ 1,453	$ 1,098	$ 1,411	$ 1,056
Interest income recognized	39	32	76	63
Global Consumer Services Group [Member] | Card Member Loans [Member]
Financing Receivable, Impaired [Line Items]
Average balance of impaired loans	1,102	846	1,076	819
Interest income recognized	33	26	64	52
Global Consumer Services Group [Member] | Card Member Receivables [Member]
Financing Receivable, Impaired [Line Items]
Average balance of impaired loans	51	31	48	29
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	195	149	188	141
Interest income recognized	6	6	12	11
Global Commercial Services [Member] | Card Member Receivables [Member]
Financing Receivable, Impaired [Line Items]
Average balance of impaired loans	105	72	99	67
Interest income recognized	$ 0	$ 0	$ 0	$ 0