Goodwill and Other Intangible Assets - Schedule of Intangible Assets and Accumulated Amortization Included in the Consolidated Statements of Condition (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Intangible Assets [Line Items]
Gross Carrying Amount	$ 415	$ 427
Accumulated Amortization	(272)	(241)
Net Carrying Value	143	186
Core deposit intangibles
Intangible Assets [Line Items]
Gross Carrying Amount	356	368
Accumulated Amortization	(233)	(208)
Net Carrying Value	123	160
Client relationships
Intangible Assets [Line Items]
Gross Carrying Amount	32	32
Accumulated Amortization	(18)	(16)
Net Carrying Value	14	16
Other
Intangible Assets [Line Items]
Gross Carrying Amount	27	27
Accumulated Amortization	(21)	(17)
Net Carrying Value	$ 6	$ 10