Accounting for Transfers and Servicing of Financial Assets and Variable Interest Entities - Investments in Community Development and Tax-advantaged VIEs (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Variable Interest Entity [Line Items]
Investment carrying amount	$ 695,357	$ 678,318
Unfunded capital and other commitments	631,559	619,278
Variable Interest Entity, Not Primary Beneficiary, Community Development and Tax-Advantaged Investments
Variable Interest Entity [Line Items]
Investment carrying amount	9,535	8,107
Unfunded capital and other commitments	5,954	5,032
Maximum exposure to loss	$ 9,635	$ 8,435