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Stock-based Compensation (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2022
Mar. 31, 2021
Dec. 31, 2021
Dec. 31, 2020
Restricted Stock Units (RSUs)        
Share-based Payment activity [Roll Forward]        
Unvested at beginning of period (in shares) 912,400 1,096,200 1,096,200  
Granted (in shares) 0 56,600    
Vested (in shares) (122,800) (207,500)    
Forfeited (in shares) (2,800) (5,000.0)    
Unvested at end of period (in shares) 786,800 940,300 912,400 1,096,200
Performance Shares [Member]        
Share-based Payment activity [Roll Forward]        
Unvested at beginning of period (in shares) 646,000.0 531,500 531,500  
Granted (in shares) 0 0    
Vested (in shares) (175,100) (79,000.0)    
Forfeited (in shares) (4,800) (13,400)    
Unvested at end of period (in shares) 466,100 439,100 646,000.0 531,500
Share-based Payment Arrangement [Member]        
Share-based Payment activity [Roll Forward]        
Unvested at beginning of period (in shares) 1,558,400 1,627,700 1,627,700  
Granted (in shares) 0 56,600    
Vested (in shares) (297,900) (286,500)    
Forfeited (in shares) (7,600) (18,400)    
Unvested at end of period (in shares) 1,252,900 1,379,400 1,558,400 1,627,700
Share-based Payment activity, additional disclosures [Abstract]        
Weighted average grant date fair value, beginning of period (in dollars per share) $ 152.27 $ 137.42 $ 137.42  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value 0 145.93    
Weighted average grant date fair value, vested (in dollars per share) 150.29 150.76    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value 174.32 149.11    
Weighted average grant date fair value, end of period (in dollars per share) $ 152.62 $ 134.84 $ 152.27 $ 137.42
Weighted average remaining contractual life, unvested shares outstanding 1 year 10 months 2 days 1 year 8 months 12 days 1 year 11 months 26 days 1 year 8 months 8 days
Unamortized deferred compensation cost $ 86.5