Postretirement Benefits Other Than Pensions (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Amortization of Unrecognized Postretirement Benefit Costs	$ (25.0)	$ (16.2)	$ (8.7)
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of Unrecognized Postretirement Benefit Costs	1.2	1.2	0.6
Other Postretirement Benefit Plan, Number of Retired Employees Covered	600
Other Postretirement Benefit Plan, Number of Active Employees Covered	300
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation	2.1	2.8
Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components	0.1	0.1
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	1.5
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	$ 3.7
Medical Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year	8.50%	7.00%
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Future Years	5.00%	5.00%
Prescription Drug Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year	8.00%	8.50%
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Future Years	5.00%	5.00%