Loans and Card Member Receivables (Details 3) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Impaired loans and receivables
Loans over 90 days past due and accruing interest	$ 152	$ 226
Non-accrual loans	105	176
Loans and receivables modified as a Troubled Debt Restructuring in Program	1,889	3,086
Loans and receivables modified as Troubled Debt Restructuring Out of Program	1,303	430
Total impaired loans and receivables	3,449	3,918
Reserve for Credit Losses - TDRs	1,035	1,346
Accounts Receivable and Loans Textuals
Total loans and receivables modified as a TDR, past due 90 days and still accruing	29	32
Total loans and receivables modified as a TDR, non-accrual	11	11
Out of Program TDR accounts that completed modification programs	1,140	316
Out of Program TDR accounts not in compliance with modification programs	163	114
Other Loans
Impaired loans and receivables
Loans over 90 days past due and accruing interest	1	2
Non-accrual loans	1	1
Loans and receivables modified as a Troubled Debt Restructuring in Program	140	248
Loans and receivables modified as Troubled Debt Restructuring Out of Program	5	6
Total impaired loans and receivables	147	257
Reserve for Credit Losses - TDRs	13	80
GCSG | Card Member Loans
Impaired loans and receivables
Loans over 90 days past due and accruing interest	136	203
Non-accrual loans	88	146
Loans and receivables modified as a Troubled Debt Restructuring in Program	1,057	1,586
Loans and receivables modified as Troubled Debt Restructuring Out of Program	729	248
Total impaired loans and receivables	2,010	2,183
Reserve for Credit Losses - TDRs	655	782
GCSG | Card Member Receivables
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	154	240
Loans and receivables modified as Troubled Debt Restructuring Out of Program	86	34
Total impaired loans and receivables	240	274
Reserve for Credit Losses - TDRs	52	60
GCS | Card Member Loans
Impaired loans and receivables
Loans over 90 days past due and accruing interest	15	21
Non-accrual loans	16	29
Loans and receivables modified as a Troubled Debt Restructuring in Program	256	478
Loans and receivables modified as Troubled Debt Restructuring Out of Program	263	67
Total impaired loans and receivables	550	595
Reserve for Credit Losses - TDRs	229	285
GCS | Card Member Receivables
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	282	534
Loans and receivables modified as Troubled Debt Restructuring Out of Program	220	75
Total impaired loans and receivables	502	609
Reserve for Credit Losses - TDRs	$ 86	$ 139