v3.24.0.1
INCOME TAXES - Effective income tax rate on earnings (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Reconciliation of effective tax rate on earnings (loss) from continuing operations before income taxes and the U.S. federal income tax statutory rate      
Income tax expense (benefit) at the federal statutory rate $ (82.5) $ (203.9) $ (268.8)
Effect of:      
State income taxes (14.7) (30.9) (46.9)
Increase in reserve for uncertain tax positions (0.2)   (3.3)
Federal and state credits (1.3) (2.5) (2.3)
Permanent items - other (17.6) 5.2 (3.1)
Foreign rate differential (3.6) (11.0) 4.3
Original issue discount   (152.5)  
Other 1.2 (14.2) (5.0)
Impact of UK tax rate change     (34.3)
Valuation allowance 122.1 412.3 349.2
Income tax provision (benefit) $ 3.4 $ 2.5 $ (10.2)
Effective income tax rate (as a percent) (0.90%) (0.30%) 0.80%