Goodwill and Other Intangible Assets - Summary Of Intangible Assets and Accumulated Amortization Included In The Consolidated Statements of Condition (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Intangible Assets [Line Items]
Gross Carrying Amount	$ 449	$ 449
Accumulated Amortization	(151)	(95)
Net Carrying Value	298	354
Core deposit intangibles
Intangible Assets [Line Items]
Gross Carrying Amount	371	371
Accumulated Amortization	(128)	(81)
Net Carrying Value	243	290
Client relationships
Intangible Assets [Line Items]
Gross Carrying Amount	37	37
Accumulated Amortization	(11)	(8)
Net Carrying Value	26	29
Other
Intangible Assets [Line Items]
Gross Carrying Amount	41	41
Accumulated Amortization	(12)	(6)
Net Carrying Value	$ 29	$ 35