Goodwill and Other Intangible Assets - Summary of Intangible Assets and Accumulated Amortization Included in the Consolidated Statements of Condition (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Intangible Assets [Line Items]
Gross Carrying Amount	$ 430	$ 449
Accumulated Amortization	(184)	(151)
Net Carrying Value	246	298
Core deposit intangibles
Intangible Assets [Line Items]
Gross Carrying Amount	371	371
Accumulated Amortization	(161)	(128)
Net Carrying Value	210	243
Client relationships
Intangible Assets [Line Items]
Gross Carrying Amount	32	37
Accumulated Amortization	(12)	(11)
Net Carrying Value	20	26
Other
Intangible Assets [Line Items]
Gross Carrying Amount	27	41
Accumulated Amortization	(11)	(12)
Net Carrying Value	$ 16	$ 29