Annual report pursuant to Section 13 and 15(d)

Pension And Other Postretirement Benefit Programs Summary of Balance Sheet Impact of Postretirement Benefit Plans, Related Benefit Obligations, Assets, Funded Status Rate Assumptions (Details)

v3.20.4
Pension And Other Postretirement Benefit Programs Summary of Balance Sheet Impact of Postretirement Benefit Plans, Related Benefit Obligations, Assets, Funded Status Rate Assumptions (Details) - USD ($)
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Postretirement Benefits Plan      
Defined Benefit Plan Disclosure [Line Items]      
Benefit obligations as of beginning of period $ 65,300,000 $ 62,200,000  
Service cost 0 200,000 $ 400,000
Interest cost 1,900,000 2,500,000 2,600,000
Plan participants' contributions 1,200,000 2,200,000  
Actuarial loss (4,500,000) (10,000,000.0)  
Benefits paid 6,900,000 9,200,000  
Benefit obligation as of end of period 59,600,000 65,300,000 62,200,000
Fair value of plan assets as of beginning of period 0 0  
Employer contribution 5,700,000 7,000,000.0  
Plan participants' contribution 1,200,000 2,200,000  
Benefits paid 6,900,000 9,200,000  
Fair value of plan assets as of end of period 0 0 0
Funded status of the plans (59,600,000) (65,300,000)  
Pension Plan | United States      
Defined Benefit Plan Disclosure [Line Items]      
Benefit obligations as of beginning of period 394,600,000 346,400,000  
Service cost 2,600,000 2,700,000 3,800,000
Interest cost 12,500,000 15,000,000.0 14,600,000
Effect of plan curtailment (900,000) 0  
Actuarial loss (30,400,000) (49,200,000)  
Benefits paid 20,800,000 18,700,000  
Benefit obligation as of end of period 418,400,000 394,600,000 346,400,000
Fair value of plan assets as of beginning of period 380,700,000 337,100,000  
Employer contribution 100,000 100,000  
Benefits paid 20,800,000 18,700,000  
Fair value of plan assets as of end of period 417,200,000 380,700,000 $ 337,100,000
Funded status of the plans $ (1,200,000) $ (13,900,000)