Annual report pursuant to Section 13 and 15(d)

STOCK COMPENSATION PLANS - Nonemployee Directors (Details)

v3.22.0.1
STOCK COMPENSATION PLANS - Nonemployee Directors (Details) - USD ($)
12 Months Ended
Mar. 13, 2020
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Compensation cost related to outstanding awards not yet recognized   $ 24,000,000    
Restricted Stock Units (RSUs)        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Granted (in shares)   678,420 960,637 572,104
Restricted Stock Units (RSUs) | AK Steel        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Granted (in shares) 300,000 0 200,291 0
Share-based Payment Arrangement, Nonemployee | Director | Directors Plan | Restricted Stock Units (RSUs)        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Compensation cost related to outstanding awards not yet recognized   $ 120,000 $ 100,000 $ 100,000
Granted (in shares)   58,851 253,809 86,477
Share-based Payment Arrangement, Nonemployee | Director | Deferred shares | Directors Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Granted (in shares)   13,078 54,794 23,659