Pension Benefits and Postretirement Benefits Other Than Pensions (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($) employees	Mar. 31, 2015 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Future Effect of Plan Amendment on Net Periodic Benefit Cost	$ 1.0
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	2.2	$ 2.6
Interest Cost on Projected Benefit Obligation	5.4	6.4
Expected Return on Plan Assets	(8.2)	(8.8)
Amortization of Accumulated Net Unrecognized Pension Costs	3.0	5.8
Total Expense (Benefit) Recognized	$ 2.4	6.0
Postretirement Benefits Other than Pensions [Member]
Defined Benefit Plan Disclosure [Line Items]
Other Postretirement Benefit Plan, Number of Retired Employees Covered | employees	500
Service Cost	$ 0.0	0.0
Interest Cost on Projected Benefit Obligation	0.2	0.3
Amortization of Accumulated Net Unrecognized Pension Costs	(0.3)	(0.4)
Total Expense (Benefit) Recognized	$ (0.1)	$ (0.1)
Other Postretirement Benefit Plan, Number of Active Employees Covered | employees	225
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Pension Plan, Number of Participants and Beneficiaries | employees	9,200
Defined Benefit Pension Plans, Number of Active Employees | employees	1,800