Loan Receivables and Allowance for Credit Losses - Loans Entered into a Loan Modification Program (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Modification Date Amount
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total loans entered into a modification program	$ 562	$ 612	$ 1,722	$ 1,901
% of Total Class of Loan Receivables	0.50%	0.60%	1.70%	1.90%
Short-term Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total loans entered into a modification program			$ 120
Long-term Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total loans entered into a modification program			914
Credit cards \| Short-term Payment Deferral \| Modification Date Amount
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total loans entered into a modification program	$ 191	$ 203	$ 605	$ 664
% of Total Class of Loan Receivables	0.20%	0.20%	0.60%	0.70%
Credit cards \| Long-term Payment Deferral \| Modification Date Amount
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total loans entered into a modification program	$ 364	$ 406	$ 1,103	$ 1,228
% of Total Class of Loan Receivables	0.40%	0.40%	1.20%	1.30%
Consumer installment loans \| Short-term Payment Deferral \| Modification Date Amount
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total loans entered into a modification program	$ 0	$ 0	$ 0	$ 0
% of Total Class of Loan Receivables	0.00%	0.00%	0.00%	0.00%
Consumer installment loans \| Long-term Payment Deferral \| Modification Date Amount
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total loans entered into a modification program	$ 0	$ 0	$ 0	$ 0
% of Total Class of Loan Receivables	0.00%	0.00%	0.00%	0.00%
Commercial credit products \| Short-term Payment Deferral \| Modification Date Amount
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total loans entered into a modification program	$ 1	$ 1	$ 2	$ 2
% of Total Class of Loan Receivables	0.00%	0.00%	0.10%	0.00%
Commercial credit products \| Long-term Payment Deferral \| Modification Date Amount
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total loans entered into a modification program	$ 6	$ 2	$ 12	$ 7
% of Total Class of Loan Receivables	0.20%	0.10%	0.50%	0.40%