EARNINGS PER COMMON SHARE - Computation of Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Net income	$ 109	$ 102	$ 162	$ 195
Less: Preferred stock dividends	2	2	4	4
Net income available to common stockholders	107	100	158	191
Net income available to common stockholders	$ 107	$ 100	$ 158	$ 191
Basic weighted average common shares outstanding (in shares)	351,269,791	319,599,352	347,830,430	320,283,480
Net effect of dilutive stock options, warrants and restricted stock (in shares)	3,417,278	3,728,813	4,004,504	3,744,783
Diluted weighted average common shares outstanding (in shares)	354,687,069	323,328,165	351,834,934	324,028,263
Earnings per common share:
Basic (in dollars per share)	$ 0.30	$ 0.31	$ 0.45	$ 0.60
Diluted (in dollars per share)	$ 0.30	$ 0.31	$ 0.45	$ 0.59