Derivatives - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Derivative Instruments, Gain (Loss) [Line Items]
Collateral cash payables	$ 271		$ 271		$ 440
Total trading revenues	34	$ 31	70	$ 75
Hedged amount of foreign currency denominated loans	5		5		16
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	11		11		5
Net fair value of derivative liabilities with adjustable posting thresholds	109		109		187
Collateral received	69		69		82
Securities posted collateral	63		63		96
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	11		11		6
Net fair value of derivative liabilities with adjustable posting thresholds	109		109		187
Collateral received	69		69		82
Securities posted collateral	63		63		96
Credit Risk Contract
Derivative Instruments, Gain (Loss) [Line Items]
Derivative asset, notional amount	220		220		268
Derivative liability, notional amount	936		936		916
Visa Class B Shares
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liabilities related to sale	13		13		15
Derivative valuation adjustment			5		15
Counterparties
Derivative Instruments, Gain (Loss) [Line Items]
Collateral cash receivables	323		323		541
Collateral cash payables	$ 18		$ 18		$ 25