XML 72 R61.htm IDEA: XBRL DOCUMENT v3.10.0.1
Schedule of Employee Benefit Plans Components of Net Periodic Benefit Cost (Credit) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Mar. 31, 2017
Jun. 30, 2018
Jun. 30, 2017
Supplemental Executive Retirement Plan (SERP) [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment $ 11.6        
Pension Plan [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Service cost 1.0 $ 1.1   $ 2.1 $ 1.9
Interest cost 6.8 7.4   13.7 14.2
Expected asset return (11.5) (11.1)   (23.0) (21.6)
Amortized loss 2.2 1.8   4.4 3.5
Curtailment 0.0 0.0   3.2 0.0
Amortized prior service credit 0.1 0.0   0.1 0.0
Net periodic benefit cost (credit) (1.4) $ (0.8)   0.5 (2.0)
Other Postretirement Benefits Plan [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Service cost 0.1   $ 0.1 0.2 0.2
Interest cost 3.1   3.3 6.2 6.6
Amortized loss 0.2   0.1 0.4 0.3
Amortized prior service credit (0.6)   (0.6) (1.3) (1.3)
Net periodic benefit cost 2.8   $ 2.9 5.5 $ 5.8
Other Operating Income (Expense) [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Components of net periodic benefit cost other than service cost $ 0.3     $ 0.5