Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets
Gross Carrying Amount	$ 361	$ 361
Accumulated Amortization	(246)	(236)
Net Carrying Amount	115	125
Core deposit intangibles
Finite-Lived Intangible Assets
Gross Carrying Amount	209	209
Accumulated Amortization	(189)	(184)
Net Carrying Amount	20	25
Developed technology
Finite-Lived Intangible Assets
Gross Carrying Amount	106	106
Accumulated Amortization	(37)	(33)
Net Carrying Amount	69	73
Customer relationships
Finite-Lived Intangible Assets
Gross Carrying Amount	30	30
Accumulated Amortization	(11)	(10)
Net Carrying Amount	19	20
Other
Finite-Lived Intangible Assets
Gross Carrying Amount	16	16
Accumulated Amortization	(9)	(9)
Net Carrying Amount	$ 7	$ 7