Annual report pursuant to Section 13 and 15(d)

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

v3.10.0.1
Postretirement Benefits Benefit Obligations, Plan Assets and Funded Status (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Change in Plan Assets [Roll Forward]      
Funded Percentage [1] 98.34559% 76.1752%  
Pension Plans [Member]      
Change in Benefit Obligations [Roll Forward]      
Benefit Obligation at Previous December 31 $ 716.9 $ 921.5  
Interest Cost 22.6 28.4 $ 35.8
Participant Contributions 0.0 0.0  
Actuarial (Gains) Losses (42.9) 58.0  
Benefit Payments (43.8) (56.6)  
Settlement Payments 0.0 (234.4)  
Benefit Obligation at December 31 652.8 716.9 921.5
Change in Plan Assets [Roll Forward]      
Fair Value of Plan Assets at Previous December 31 546.1 687.9  
Actual Return on Plan Assets (24.1) 75.5  
Employer Contributions 163.8 73.7  
Participant Contributions 0.0 0.0  
Benefit Payments (43.8) (56.6)  
Settlement Payments 0.0 (234.4)  
Fair Value of Plan Assets at December 31 642.0 546.1 687.9
Funded Status at December 31 (10.8) (170.8)  
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]      
Asset, Defined Benefit Plan, Prepaid Expenses and Other 14.8 0.0  
Assets, Defined Benefit Plan, Accounts and Notes Receivable 3.6 3.5  
Assets for Plan Benefits, Defined Benefit Plan 18.4 3.5  
Liability, Defined Benefit Plan, Current 3.7 3.8  
Liability, Defined Benefit Plan, Noncurrent 25.5 170.5  
Liability, Defined Benefit Plan 29.2 174.3  
Other Postretirement Benefit Plans [Member]      
Change in Benefit Obligations [Roll Forward]      
Benefit Obligation at Previous December 31 38.7 40.6  
Interest Cost 1.1 1.2 1.4
Participant Contributions 0.2 0.5  
Actuarial (Gains) Losses (2.5) 0.0  
Benefit Payments (3.2) (3.6)  
Settlement Payments 0.0 0.0  
Benefit Obligation at December 31 34.3 38.7 40.6
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 3.0 3.1  
Participant Contributions 0.2 0.5  
Benefit Payments (3.2) (3.6)  
Settlement Payments 0.0 0.0  
Fair Value of Plan Assets at December 31 0.0 0.0 $ 0.0
Funded Status at December 31 (34.3) (38.7)  
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 3.7  
Liability, Defined Benefit Plan, Noncurrent 30.7 35.0  
Liability, Defined Benefit Plan 34.3 38.7  
Nonqualified Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation $ 29.2 $ 33.2  
[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 and 2017, the plan assets for the Company's Salaried and Bargaining plans were in excess of the projected and accumulated benefit obligations