Commitments and Contingencies - Other Commitments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Dec. 31, 2025
Loss Contingencies [Line Items]
Payment for half of subscribed shares	$ 5,400	$ 5,400
Resale And Forward-Dated Resale And Securities Borrowing Agreements And Forward-Dated Repurchase And Securities Lending Agreements
Loss Contingencies [Line Items]
Other commitment, expiration term (in months)	12 months
Resale and Forward-Dated Resale and Securities Borrowing Agreements
Loss Contingencies [Line Items]
Other commitments	$ 236,400	149,000
Forward-Dated Repurchase and Securities Lending Agreements
Loss Contingencies [Line Items]
Other commitments	147,100	108,900
Auto Loans and Leases
Loss Contingencies [Line Items]
Other commitment, due in next twelve months	$ 3,900	4,000
Other commitment, termination prior notice period	12 months
Debt and Equity Security Commitments
Loss Contingencies [Line Items]
Other commitments	$ 850	884
Residential and Commercial Portfolio Segments \| Loan Purchase Commitments \| Residential and Commercial Financing Receivable
Loss Contingencies [Line Items]
Other commitments	786	700
Commercial \| Loan Purchase Commitments
Loss Contingencies [Line Items]
Other commitments	$ 518	$ 558