XML 117 R103.htm IDEA: XBRL DOCUMENT v3.22.4
Defined Benefit Plans - Obligations and Funded Status (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Change in the Projected Benefit Obligation (PBO):      
Recognition of actuarial losses (gains) $ (1.2) $ 0.8 $ 3.2
Change in Plan Assets:      
Beginning balance 649.8    
Ending balance 482.5 649.8  
Pension Benefits [Member]      
Change in the Projected Benefit Obligation (PBO):      
Projected benefit obligation at beginning of year 712.0 750.6  
Service cost 0.2 0.4  
Interest cost 20.4 19.3  
Recognition of actuarial losses (gains) (155.9) (26.2)  
Benefits paid (33.1) (32.1)  
Projected benefit obligation at end of year 543.6 712.0 750.6
Accumulated benefit obligation at end of year (excludes the impact of future compensation increases) 543.6 712.0  
Change in Plan Assets:      
Beginning balance 649.8 624.2  
Actual return on plan assets (144.8) 37.8  
Employer contributions (10.6) (19.9)  
Benefits paid (33.1) (32.1)  
Ending balance 482.5 649.8 624.2
Funded status (Fair value of plan assets less PBO) (61.1) (62.2)  
Postretirement Benefits [Member]      
Change in the Projected Benefit Obligation (PBO):      
Projected benefit obligation at beginning of year 9.8 10.6  
Service cost 0.4 0.2  
Interest cost 0.4 0.2  
Recognition of actuarial losses (gains) (1.2) (1.0)  
Benefits paid (0.4) (0.2)  
Projected benefit obligation at end of year 9.0 9.8 $ 10.6
Change in Plan Assets:      
Employer contributions (0.4) (0.1)  
Benefits paid (0.4) 0.1  
Funded status (Fair value of plan assets less PBO) $ (9.0) $ (9.8)