Schedule of Employee Benefit Plans Components of Net Periodic Benefit Cost (Credit) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 0.7	$ 0.8	$ 2.6	$ 2.3
Interest cost	7.2	7.3	21.4	21.9
Expected asset return	(11.1)	(10.7)	(32.7)	(32.1)
Amortized loss	1.9	1.3	5.4	4.1
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	2.9	0.0	2.9	0.0
Net periodic benefit cost (credit)	1.5	(1.3)	(0.5)	(3.8)
Amortized prior service credit	(0.1)	0.0	(0.1)	0.0
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.1	0.1	0.3	0.3
Interest cost	3.3	3.5	9.9	10.5
Amortized loss	0.2	0.1	0.5	0.3
Amortized prior service credit	(0.8)	(0.7)	(2.1)	(2.0)
Net periodic benefit cost	$ 2.8	$ 3.0	$ 8.6	$ 9.1