Retirement Plans (Details) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) plan	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributory defined benefit pension plans | plan			4
Net periodic pension cost [Abstract]
Employer service cost - benefits earned during the period	$ 1.3	$ 1.0	$ 3.9	$ 2.9
Interest cost on projected benefit obligation	3.7	4.1	11.0	12.3
Expected return on plan assets	(5.3)	(6.2)	(15.8)	(18.6)
Net amortization of deferrals	(0.8)	(0.3)	(2.4)	(0.8)
Recognized actuarial loss	0.4	0.0	1.2	0.1
Net periodic pension cost (income)	0.9	(0.8)	$ 2.7	(2.5)
Pension Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Minimum expected return on plan assets (in hundredths)			2.70%
Maximum expected return on plan assets (in hundredths)			5.80%
Contributions [Abstract]
Contributions to defined benefit pension plans	3.9	$ 5.4	$ 9.3	$ 12.0	$ 14.6
Expected contributions in remainder of fiscal year			3.1
Total contributions in fiscal year	$ 12.4		$ 12.4