Annual report pursuant to Section 13 and 15(d)

Postretirement Benefits Benefit Obligations, Plan Assets and Funded Status (Details)

v3.19.3.a.u2
Postretirement Benefits Benefit Obligations, Plan Assets and Funded Status (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Change in Plan Assets [Roll Forward]      
Funded Percentage [1] 38.00% 98.00%  
Pension Plans [Member]      
Change in Benefit Obligations [Roll Forward]      
Benefit Obligation at Previous December 31 $ 652.8 $ 716.9  
Interest Cost 6.0 22.6 $ 28.4
Participant Contributions 0.0 0.0  
Actuarial (Gains) Losses 77.3 (42.9)  
Benefit Payments (34.1) (43.8)  
Settlement Payments (673.9) 0.0  
Benefit Obligation at December 31 28.1 652.8 716.9
Change in Plan Assets [Roll Forward]      
Fair Value of Plan Assets at Previous December 31 642.0 546.1  
Actual Return on Plan Assets 70.8 (24.1)  
Employer Contributions 7.9 163.8  
Participant Contributions 0.0 0.0  
Benefit Payments (34.1) (43.8)  
Settlement Payments (673.9) 0.0  
Defined Benefit Plan, Plan Assets, Adjustments (2.1) 0.0  
Fair Value of Plan Assets at December 31 10.6 642.0 546.1
Funded Status at December 31 (17.5) (10.8)  
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]      
Asset, Defined Benefit Plan, Prepaid Expenses and Other 0.0 14.8  
Assets, Defined Benefit Plan, Accounts and Notes Receivable 10.6 3.6  
Assets for Plan Benefits, Defined Benefit Plan 10.6 18.4  
Liability, Defined Benefit Plan, Current 3.5 3.7  
Liability, Defined Benefit Plan, Noncurrent 24.6 25.5  
Liability, Defined Benefit Plan 28.1 29.2  
Other Postretirement Benefit Plans [Member]      
Change in Benefit Obligations [Roll Forward]      
Benefit Obligation at Previous December 31 34.3 38.7  
Interest Cost 1.3 1.1 1.2
Participant Contributions 0.0 0.2  
Actuarial (Gains) Losses 0.2 (2.5)  
Benefit Payments (2.8) (3.2)  
Settlement Payments 0.0 0.0  
Benefit Obligation at December 31 33.0 34.3 38.7
Change in Plan Assets [Roll Forward]      
Fair Value of Plan Assets at Previous December 31 0.0 0.0  
Actual Return on Plan Assets 0.0 0.0  
Employer Contributions 2.8 3.0  
Participant Contributions 0.0 0.2  
Benefit Payments (2.8) (3.2)  
Settlement Payments 0.0 0.0  
Defined Benefit Plan, Plan Assets, Adjustments 0.0 0.0  
Fair Value of Plan Assets at December 31 0.0 0.0 $ 0.0
Funded Status at December 31 (33.0) (34.3)  
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]      
Asset, Defined Benefit Plan, Prepaid Expenses and Other 0.0 0.0  
Assets, Defined Benefit Plan, Accounts and Notes Receivable 0.0 0.0  
Assets for Plan Benefits, Defined Benefit Plan 0.0 0.0  
Liability, Defined Benefit Plan, Current 3.6 3.6  
Liability, Defined Benefit Plan, Noncurrent 29.4 30.7  
Liability, Defined Benefit Plan 33.0 34.3  
Nonqualified Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation 28.1 29.2  
Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation $ 28.1 $ 29.2  
[1] (A) As all of the Company's plans are frozen, the projected benefit obligation and the accumulated benefit obligation are equal. As of December 31, 2018, the plan assets for the Company's Salaried and Bargaining plans were in excess of the projected and accumulated benefit obligations