STOCKHOLDERS' EQUITY - Narrative (Details) $ / shares in Units, $ in Millions		12 Months Ended
	Mar. 12, 2020 USD ($) $ / shares shares	Dec. 31, 2024 vote $ / shares	Dec. 31, 2023 $ / shares	Jan. 03, 2022 $ / shares
Class of Stock [Line Items]
Depositary shares, shares issued (in shares) | shares	13,800,000
Depository shares, percentage of preferred stock	0.025
Depository shares, equivalent value per preferred share	$ 1,000
Depositary shares, shares issued, value | $	$ 345
CIT Group Inc.
Class of Stock [Line Items]
Common stock, par value (in dollars per share)				$ 0.01
Class A
Class of Stock [Line Items]
Common stock, par value (in dollars per share)		$ 1	$ 1
Common stock, voting right per share | vote		1
Class B
Class of Stock [Line Items]
Common stock, par value (in dollars per share)		$ 1	$ 1
Common stock, voting right per share | vote		16
Series A
Class of Stock [Line Items]
Dividend	5.375%	5.375%
Series B | CIT Group Inc.
Class of Stock [Line Items]
Common stock, terms of conversion, conversion ratio				1
Series C
Class of Stock [Line Items]
Dividend		5.625%
Series C | CIT Group Inc.
Class of Stock [Line Items]
Common stock, terms of conversion, conversion ratio				1