Employee Retirement Plans and Postretirement Benefits Amortization Amounts Expected (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Amortization of net prior service cost (gain)	$ 0.4
Amortization of actuarial net loss (gain)	(9.3)
Pension
Defined Benefit Plan Disclosure [Line Items]
Amortization of net prior service cost (gain)	0.6
Amortization of actuarial net loss (gain)	(9.3)
OPEB
Defined Benefit Plan Disclosure [Line Items]
Amortization of net prior service cost (gain)	(0.2)
Amortization of actuarial net loss (gain)	$ 0