Loans and Card Member Receivables - Card Member Receivables (Details) - Card Member receivables - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	$ 62,031	$ 59,411
Financing receivables, reserves for credit losses	180	171	$ 174	$ 229
Financing receivables, net	61,851	59,240
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	26,605	25,431
Small Business
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	19,558	18,619
Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	15,868	15,361
Variable Interest Entity, Primary Beneficiary
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	5,659	3,927
Variable Interest Entity, Primary Beneficiary | Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	$ 5,700	$ 3,900