Loan Receivables and Allowance for Credit Losses - Loans Entered into a Loan Modification Program (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Modification Date Amount
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total loans entered into a modification program	$ 591	$ 638	$ 1,289	$ 1,358
% of Total Class of Loan Receivables	0.60%	0.60%	1.30%	1.30%
Short-term Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total loans entered into a modification program			$ 124
Long-term Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total loans entered into a modification program			732
Credit cards \| Short-term Payment Deferral \| Modification Date Amount
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total loans entered into a modification program	$ 206	$ 226	$ 461	$ 473
% of Total Class of Loan Receivables	0.20%	0.20%	0.50%	0.50%
Credit cards \| Long-term Payment Deferral \| Modification Date Amount
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total loans entered into a modification program	$ 383	$ 409	$ 822	$ 880
% of Total Class of Loan Receivables	0.40%	0.40%	0.90%	0.90%
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	$ 0	$ 1	$ 1	$ 1
% of Total Class of Loan Receivables	0.00%	0.00%	0.00%	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	$ 2	$ 2	$ 5	$ 4
% of Total Class of Loan Receivables	0.10%	0.10%	0.30%	0.20%