Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Millions	Total	Class A Common Stock	Class B Common Stock	Series A Preferred Stock	Series B Preferred Stock	Series C Preferred Stock	Preferred Stock	Preferred Stock Series B Preferred Stock	Preferred Stock Series C Preferred Stock	Common Stock Class A Common Stock	Common Stock Class B Common Stock	Additional Paid in Capital	Retained Earnings	Retained Earnings Class A Common Stock	Retained Earnings Class B Common Stock	Retained Earnings Series A Preferred Stock	Retained Earnings Series B Preferred Stock	Retained Earnings Series C Preferred Stock	Accumulated Other Comprehensive (Loss) Income
Beginning balance, shareholders' equity at Dec. 31, 2021	$ 4,738						$ 340			$ 9	$ 1	$ 0	$ 4,378						$ 10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	271												271
Other comprehensive (loss) income, net of tax	(315)																		(315)
Stock based compensation	71											71
Cash dividends declared		$ (7)	$ 0											$ (7)	$ 0
Preferred stock dividends declared					$ (5)	$ (3)											$ (5)	$ (3)
Issued in CIT Merger:	5,279				334	207		$ 334	$ 207	6		5,273
Ending balance, shareholders' equity at Mar. 31, 2022	10,570						881			15	1	5,344	4,634						(305)
Beginning balance, shareholders' equity at Dec. 31, 2022	9,662						881			14	1	4,109	5,392						(735)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	9,518												9,518
Other comprehensive (loss) income, net of tax	66																		66
Stock based compensation	(5)											(5)
Cash dividends declared		$ (10)	$ (1)											$ (10)	$ (1)
Preferred stock dividends declared				$ (4)	$ (7)	$ (3)										$ (4)	$ (7)	$ (3)
Ending balance, shareholders' equity at Mar. 31, 2023	$ 19,216						$ 881			$ 14	$ 1	$ 4,104	$ 14,885						$ (669)