Derivatives and Hedging Activities - Narrative (Details)	9 Months Ended
	Sep. 30, 2025 USD ($) group	Dec. 31, 2024 USD ($)
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Loss expected to be reclassified	$ 92,000,000
Reclassification of net losses related to terminated cash flow hedges from AOCI to income	$ 3,000,000
Maximum length of time over which forecasted transactions are hedged (in years)	4 years 3 days
Cash collateral netted against derivative assets	$ 77,000,000	$ 75,000,000
Collateral netted against derivative liabilities	$ 82,000,000	124,000,000
Number of derivative transactions group | group	2
Gross exposure on derivatives, after taking into account the effects of bilateral collateral and master netting agreements	$ 235,000,000
Net exposure on derivatives, after taking into account, the effects of bilateral collateral and master netting agreements	44,000,000
Over collateralization on derivatives to broker dealers and banks after application of master netting agreements and collateral		247,000,000
Debt securities, available for sale and held to maturity, additional collateral pledged	0	42,000,000
Default reserve associated with uncollateralized contracts	6,000,000	4,000,000
Gross exposure on derivatives after taking into account effects of master netting agreements	206,000,000	239,000,000
Net exposure on derivatives with clients after application of master netting agreements collateral and related reserve	$ 186,000,000	$ 207,000,000