Loans and Card Member Receivables - Performance (Details 5) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances		$ 1,733
Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	$ 667
30-89 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	113
90+ Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	27
Card Member Loans | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances		781
Card Member Loans | Small Business
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances		267
Card Member Loans | Corporate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances		0
Card Member Loans | Current | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	273
Card Member Loans | Current | Small Business
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	119
Card Member Loans | Current | Corporate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	0
Card Member Loans | 30-89 Days Past Due | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	43
Card Member Loans | 30-89 Days Past Due | Small Business
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	20
Card Member Loans | 30-89 Days Past Due | Corporate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	0
Card Member Loans | 90+ Days Past Due | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	13
Card Member Loans | 90+ Days Past Due | Small Business
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	5
Card Member Loans | 90+ Days Past Due | Corporate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	0
Card Member Receivables | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances		257
Card Member Receivables | Small Business
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances		403
Card Member Receivables | Corporate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances		6
Card Member Receivables | Current | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	100
Card Member Receivables | Current | Small Business
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	157
Card Member Receivables | Current | Corporate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	7
Card Member Receivables | 30-89 Days Past Due | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	14
Card Member Receivables | 30-89 Days Past Due | Small Business
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	36
Card Member Receivables | 30-89 Days Past Due | Corporate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	0
Card Member Receivables | 90+ Days Past Due | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	3
Card Member Receivables | 90+ Days Past Due | Small Business
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	6
Card Member Receivables | 90+ Days Past Due | Corporate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	0
Other Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances		$ 19
Other Loans | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	11
Other Loans | 30-89 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	0
Other Loans | 90+ Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Account Balances	$ 0