Loans and Accounts Receivable (Details 4) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Impaired loans and receivables
Loans over 90 days past due and accruing interest	$ 327	$ 260	$ 216
Non-accrual loans	199	169	150
Loans and receivables modified as a Troubled Debt Restructuring in Program	261	230	199
Loans and receivables modified as Troubled Debt Restructuring Out of Program	186	171	113
Total impaired loans and receivables	973	830	678
Unpaid principal balance	892	767	632
Related allowance for Troubled Debt Restructurings	60	88	73
Accounts Receivable and Loans (Textuals) [Abstract]
Total loans and receivables modified as a TDR, non-accrual	5	11	18
Total loans and receivables modified as a TDR, past due 90 days and still accruing	15	20	20
Out of Program TDR accounts that completed modification programs	141	132	84
Out of Program TDR accounts not in compliance with modification programs	45	39	29
U S Consumer Services [Member] | Card Member Loans [Member]
Impaired loans and receivables
Loans over 90 days past due and accruing interest	233	178	140
Non-accrual loans	168	139	124
Loans and receivables modified as a Troubled Debt Restructuring in Program	178	165	149
Loans and receivables modified as Troubled Debt Restructuring Out of Program	131	129	89
Total impaired loans and receivables	710	611	502
Unpaid principal balance	639	558	463
Related allowance for Troubled Debt Restructurings	49	51	44
U S Consumer Services [Member] | Card Member Receivables [Member]
Impaired loans and receivables
Loans over 90 days past due and accruing interest	0	0	0
Non-accrual loans	0	0	0
Loans and receivables modified as a Troubled Debt Restructuring in Program	15	11	11
Loans and receivables modified as Troubled Debt Restructuring Out of Program	9	6	3
Total impaired loans and receivables	24	17	14
Unpaid principal balance	24	17	14
Related allowance for Troubled Debt Restructurings	1	7	8
International Consumer and Network Services [Member] | Card Member Loans [Member]
Impaired loans and receivables
Loans over 90 days past due and accruing interest	56	52	52
Non-accrual loans	0	0	0
Loans and receivables modified as a Troubled Debt Restructuring in Program	0	0	0
Loans and receivables modified as Troubled Debt Restructuring Out of Program	0	0	0
Total impaired loans and receivables	56	52	52
Unpaid principal balance	55	51	51
Related allowance for Troubled Debt Restructurings	0	0	0
Global Commercial Services [Member] | Card Member Loans [Member]
Impaired loans and receivables
Loans over 90 days past due and accruing interest	38	30	24
Non-accrual loans	31	30	26
Loans and receivables modified as a Troubled Debt Restructuring in Program	31	26	23
Loans and receivables modified as Troubled Debt Restructuring Out of Program	27	26	18
Total impaired loans and receivables	127	112	91
Unpaid principal balance	118	103	85
Related allowance for Troubled Debt Restructurings	8	9	9
Global Commercial Services [Member] | Card Member Receivables [Member]
Impaired loans and receivables
Loans over 90 days past due and accruing interest	0	0	0
Non-accrual loans	0	0	0
Loans and receivables modified as a Troubled Debt Restructuring in Program	37	28	16
Loans and receivables modified as Troubled Debt Restructuring Out of Program	19	10	3
Total impaired loans and receivables	56	38	19
Unpaid principal balance	56	38	19
Related allowance for Troubled Debt Restructurings	$ 2	$ 21	$ 12