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, 2023	Dec. 31, 2022
Intangible Assets [Line Items]
Gross Carrying Amount	$ 427	$ 430
Accumulated Amortization	(241)	(196)
Net Carrying Value	186	234
Core deposit intangibles
Intangible Assets [Line Items]
Gross Carrying Amount	368	371
Accumulated Amortization	(208)	(171)
Net Carrying Value	160	200
Client relationships
Intangible Assets [Line Items]
Gross Carrying Amount	32	32
Accumulated Amortization	(16)	(13)
Net Carrying Value	16	19
Other
Intangible Assets [Line Items]
Gross Carrying Amount	27	27
Accumulated Amortization	(17)	(12)
Net Carrying Value	$ 10	$ 15