Annual report pursuant to Section 13 and 15(d)

Pension And Other Postretirement Benefit Programs - Schedule of Change in Benefit Obligation and Change in Plan Assets (Details)

v3.20.1
Pension And Other Postretirement Benefit Programs - Schedule of Change in Benefit Obligation and Change in Plan Assets (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Retiree Health and Life Insurance Plans      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment $ (2.6) $ 0.0  
Change in benefit obligation:      
Benefit obligations as of beginning of period 62.2 76.4  
Service cost 0.2 0.4 $ 0.4
Interest cost 2.5 2.6 3.2
Actuarial (gain) loss 10.0 (9.0)  
Benefits paid (9.2) (9.6)  
Benefit obligation as of end of period 65.3 62.2 76.4
Change in plan assets:      
Fair value of plan assets as of beginning of period 0.0 0.0  
Employer contribution 7.0 8.0  
Plan participants' contribution 2.2 1.6  
Benefits paid (9.2) (9.6)  
Fair value of plan assets as of end of period 0.0 0.0 0.0
Funded status of the plans (65.3) (62.2)  
U.S. Pension Plan      
Change in plan assets:      
Employer contribution 0.1 0.1  
U.S. Pension Plan | Pension Plan      
Change in benefit obligation:      
Benefit obligations as of beginning of period 346.4 395.8  
Liabilities transferred to AHF, LLC 0.0 (11.5)  
Service cost 2.7 3.8 5.4
Interest cost 15.0 14.6 15.4
Foreign currency translation adjustment 0.0 0.0  
Actuarial (gain) loss 49.2 (33.4)  
Benefits paid (18.7) (22.9)  
Benefit obligation as of end of period 394.6 346.4 395.8
Change in plan assets:      
Fair value of plan assets as of beginning of period 337.1 390.8  
Assets received from separation 0.0 (8.1)  
Actual return on plan assets 62.2 (22.8)  
Foreign currency translation adjustment 0.0 0.0  
Benefits paid (18.7) (22.9)  
Fair value of plan assets as of end of period 380.7 337.1 390.8
Funded status of the plans (13.9) (9.3)  
Accumulated benefit obligation 393.2 345.1  
Canadian Pension Plan      
Change in plan assets:      
Employer contribution 0.1 0.1  
Canadian Pension Plan | Pension Plan      
Change in benefit obligation:      
Benefit obligations as of beginning of period 15.6 17.8  
Liabilities transferred to AHF, LLC 0.0 0.0  
Service cost 0.0 0.0  
Interest cost 0.6 0.6 0.6
Foreign currency translation adjustment 0.6 (1.2)  
Actuarial (gain) loss 1.3 0.5  
Benefits paid (1.8) (2.1)  
Benefit obligation as of end of period 16.3 15.6 17.8
Change in plan assets:      
Fair value of plan assets as of beginning of period 13.6 17.1  
Assets received from separation 0.0 0.0  
Actual return on plan assets 1.7 (0.4)  
Foreign currency translation adjustment 0.6 (1.1)  
Benefits paid (1.8) (2.1)  
Fair value of plan assets as of end of period 14.2 13.6 $ 17.1
Funded status of the plans (2.1) (2.0)  
Accumulated benefit obligation $ 16.3 $ 15.6