Derivatives - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Derivative Instruments, Gain (Loss) [Line Items]
Collateral cash payables	$ 238		$ 238		$ 440
Total trading revenues	49	$ 38	119	$ 113
Hedged amount of foreign currency denominated loans	21		21		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	13		13		5
Net fair value of derivative liabilities with adjustable posting thresholds	95		95		187
Collateral received	71		71		82
Securities posted collateral	50		50		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	13		13		6
Net fair value of derivative liabilities with adjustable posting thresholds	95		95		187
Collateral received	71		71		82
Securities posted collateral	50		50		96
Credit Risk Contract
Derivative Instruments, Gain (Loss) [Line Items]
Derivative asset, notional amount	252		252		268
Derivative liability, notional amount	992		992		916
Visa Class B Shares
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liabilities related to sale	22		22		15
Derivative valuation adjustment			15		15
Counterparties
Derivative Instruments, Gain (Loss) [Line Items]
Collateral cash receivables	266		266		541
Collateral cash payables	$ 20		$ 20		$ 25