Parent Company-Only Financial Information - Cash Flows Statement (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
CASH FLOWS FROM OPERATING ACTIVITIES:
Net (loss) income		$ (1,118)	$ (79)	$ 650
Change in other assets		282	(721)	348
Change in other liabilities		(769)	(255)	(100)
Net cash provided by operating activities		86	263	1,026
CASH FLOWS FROM INVESTING ACTIVITIES:
Cash acquired in business acquisition		0	24,901	331
Net cash provided by (used in) investing activities		15,453	20,673	(6,323)
CASH FLOWS FROM FINANCING ACTIVITIES:
Treasury stock repurchased		0	0	(7)
Proceeds from common stock and warrants issued		1,004	0	0
Proceeds from preferred stock issued		1	0	0
Net cash (used in) provided by financing activities		(11,589)	(11,409)	5,168
Net increase (decrease) in cash and cash equivalents	[1]	3,950	9,527	(129)
Cash and cash equivalents at beginning of year	[1]	11,609	2,082	2,211
Cash and cash equivalents at end of year	[1]	15,559	11,609	2,082
Parent company
CASH FLOWS FROM OPERATING ACTIVITIES:
Net (loss) income		(1,118)	(79)	650
Change in other assets		1	30	(3)
Change in other liabilities		0	6	(4)
Other, net		16	65	(130)
Equity in undistributed loss (earnings) of subsidiaries		1,086	578	(196)
Net cash provided by operating activities		(15)	600	317
CASH FLOWS FROM INVESTING ACTIVITIES:
Cash acquired in business acquisition		0	0	34
Equity investment in bank subsidiary		(500)	0	0
Change in receivable from subsidiaries, net		30	(32)	5
Net cash provided by (used in) investing activities		(470)	(32)	39
CASH FLOWS FROM FINANCING ACTIVITIES:
Treasury stock repurchased		(11)	(12)	(24)
Cash dividends paid on common and preferred stock		(88)	(519)	(350)
Proceeds from common stock and warrants issued		1,004	0	0
Proceeds from preferred stock issued		1	0	0
Net cash (used in) provided by financing activities		906	(531)	(374)
Net increase (decrease) in cash and cash equivalents		421	37	(18)
Cash and cash equivalents at beginning of year		158	121	139
Cash and cash equivalents at end of year		$ 579	$ 158	$ 121

[1] For further information on restricted cash, see Note 2 - Summary of Significant Accounting Policies