Derivatives - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Derivative Instruments, Gain (Loss) [Line Items]
Collateral cash payables	$ 226		$ 210
Total trading revenues	45	$ 36
Hedged amount of foreign currency denominated loans	17		19
Additional Derivative Agreements | Derivative Instruments With Adjustable Collateral Posting Thresholds
Derivative Instruments, Gain (Loss) [Line Items]
Net fair value of derivative assets with adjustable posting thresholds	5		10
Net fair value of derivative liabilities with adjustable posting thresholds	100		92
Collateral received	61		68
Securities posted collateral	58		52
Additional Derivative Agreements | Derivative Instruments With Accelerated Termination Provisions
Derivative Instruments, Gain (Loss) [Line Items]
Net fair value of derivative assets with adjustable posting thresholds	5		11
Net fair value of derivative liabilities with adjustable posting thresholds	100		92
Collateral received	61		68
Securities posted collateral	58		52
Credit Risk Contract
Derivative Instruments, Gain (Loss) [Line Items]
Derivative asset, notional amount	323		184
Derivative liability, notional amount	1,100		1,000
Visa Class B Shares
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liabilities related to sale	18		25
Derivative valuation adjustment			25
Derivative Counterparties
Derivative Instruments, Gain (Loss) [Line Items]
Collateral cash receivables	283		243
Collateral cash payables	$ 16		$ 20