Loans - Credit Card Loan Portfolio, Delinquency and Gross Charge-offs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	$ 1,408,905	$ 1,299,590	$ 1,280,870
Total gross charge-offs	12,040	10,519	$ 7,653
Credit card
Loans and Leases Receivable Disclosure [Line Items]
Revolving loans within revolving period	245,188	231,414
Revolving loans converted to term loans	2,609	1,446
Total retained loans	$ 247,797	$ 232,860
% of 30 plus days past due to total retained loans, Revolving loans within the revolving period	2.06%	2.11%
% of 30 plus days past due to total retained loans, Revolving loans converted to term loans	12.27%	11.20%
% of 30 plus days past due to total retained loans	2.16%	2.17%
% of 90 plus days past due to total retained loans, Revolving loans within the revolving period	1.07%	1.12%
% of 90 plus days past due to total retained loans, Revolving loans converted to term loans	4.33%	3.67%
% of 90 plus days past due to total retained loans	1.10%	1.14%
Gross charge-offs originated within the revolving period	$ 8,812	$ 7,951
Gross charge-offs originated converted to term loans	352	247
Total gross charge-offs	9,164	8,198
Credit card | Current and less than 30 days past due and still accruing
Loans and Leases Receivable Disclosure [Line Items]
Revolving loans within revolving period	240,147	226,532
Revolving loans converted to term loans	2,289	1,284
Total retained loans	242,436	227,816
Credit card | 30–89 days past due and still accruing
Loans and Leases Receivable Disclosure [Line Items]
Revolving loans within revolving period	2,422	2,291
Revolving loans converted to term loans	207	109
Total retained loans	2,629	2,400
Credit card | 90 or more days past due and still accruing
Loans and Leases Receivable Disclosure [Line Items]
Revolving loans within revolving period	2,619	2,591
Revolving loans converted to term loans	113	53
Total retained loans	$ 2,732	$ 2,644