Parent Company-Only Financial Information - Income Statement (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Condensed Income Statements, Captions [Line Items]
Total interest income	$ 5,953	$ 5,491	$ 2,092
Interest expense	3,801	2,414	696
Operating expenses	2,596	2,099	604
(Loss) income before income taxes	(1,378)	(50)	826
Income tax (benefit)/expense	(260)	29	176
Net (loss) income	(1,118)	(79)	650
Parent company
Condensed Income Statements, Captions [Line Items]
Interest income	1	0	0
Dividends received from subsidiaries	67	580	335
Other income	1	2	160
Total interest income	69	582	495
Interest expense	88	82	41
Operating expenses	38	26	14
(Loss) income before income taxes	(57)	474	440
Income tax (benefit)/expense	(25)	(25)	(14)
Income before equity in undistributed (loss) earnings of subsidiaries	(32)	499	454
Equity in undistributed (loss) earnings of subsidiaries	(1,086)	(578)	196
Net (loss) income	$ (1,118)	$ (79)	$ 650