Loans and Accounts Receivable (Details 4) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Impaired loans and receivables
Loans over 90 days past due and accruing interest	$ 352	$ 327
Non-accrual loans	220	199
Loans and receivables modified as a Troubled Debt Restructuring in Program	369	261
Loans and receivables modified as Troubled Debt Restructuring Out of Program	175	186
Total impaired loans and receivables	1,116	973
Unpaid principal balance	1,022	892
Related allowance for Troubled Debt Restructurings	75	60
Accounts Receivable and Loans Textuals [Abstract]
Total loans and receivables modified as a TDR, non-accrual	4	5
Total loans and receivables modified as a TDR, past due 90 days and still accruing	15	15
Out of Program TDR accounts that completed modification programs	132	141
Out of Program TDR accounts not in compliance with modification programs	43	45
Global Consumer Services Group [Member] | Card Member Loans [Member]
Impaired loans and receivables
Loans over 90 days past due and accruing interest	308	289
Non-accrual loans	184	168
Loans and receivables modified as a Troubled Debt Restructuring in Program	245	178
Loans and receivables modified as Troubled Debt Restructuring Out of Program	118	131
Total impaired loans and receivables	855	766
Unpaid principal balance	774	694
Related allowance for Troubled Debt Restructurings	60	49
Global Consumer Services Group [Member] | Card Member Loans [Member] | Non Us [Member]
Impaired loans and receivables
Loans over 90 days past due and accruing interest	65	56
Unpaid principal balance	64	55
Global Consumer Services Group [Member] | Card Member Receivables [Member]
Impaired loans and receivables
Loans over 90 days past due and accruing interest	0	0
Non-accrual loans	0	0
Loans and receivables modified as a Troubled Debt Restructuring in Program	23	15
Loans and receivables modified as Troubled Debt Restructuring Out of Program	10	9
Total impaired loans and receivables	33	24
Unpaid principal balance	32	24
Related allowance for Troubled Debt Restructurings	2	1
Global Commercial Services [Member] | Card Member Loans [Member]
Impaired loans and receivables
Loans over 90 days past due and accruing interest	44	38
Non-accrual loans	36	31
Loans and receivables modified as a Troubled Debt Restructuring in Program	48	31
Loans and receivables modified as Troubled Debt Restructuring Out of Program	25	27
Total impaired loans and receivables	153	127
Unpaid principal balance	141	118
Related allowance for Troubled Debt Restructurings	10	8
Global Commercial Services [Member] | Card Member Receivables [Member]
Impaired loans and receivables
Loans over 90 days past due and accruing interest	0	0
Non-accrual loans	0	0
Loans and receivables modified as a Troubled Debt Restructuring in Program	53	37
Loans and receivables modified as Troubled Debt Restructuring Out of Program	22	19
Total impaired loans and receivables	75	56
Unpaid principal balance	75	56
Related allowance for Troubled Debt Restructurings	$ 3	$ 2