Pension and Postretirement Plans Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Prior Service (Cost) Benefit, Tax Effect	$ (0.1)	$ (0.1)
Prior service cost recognized:
Reclassification adjustments	0.1	0.4
Actuarial (loss) gain recognized:
Reclassification adjustments	19.1	24.9
Actuarial (loss) gain arising during the period	5.7	(20.9)
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Prior service cost (benefit)	0.0
Actuarial loss	16.5
Total	16.5
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Prior service (cost) benefit, net of tax of ($0.1), ($0.1), $10.6, $15.8	(0.1)	(0.2)
Actuarial loss, net of tax of ($81.6), ($90.4), ($19.7), ($23.0)	(141.8)	(157.8)
Total	(141.9)	(158.0)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), Tax Effect	(81.6)	(90.4)
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Prior Service (Cost) Benefit, Tax Effect	10.6	15.8
Prior service cost recognized:
Reclassification adjustments	(14.7)	(15.4)
Actuarial (loss) gain recognized:
Reclassification adjustments	4.9	5.4
Actuarial (loss) gain arising during the period	4.5	10.9
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Prior service cost (benefit)	(4.5)
Actuarial loss	4.3
Total	(0.2)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Prior service (cost) benefit, net of tax of ($0.1), ($0.1), $10.6, $15.8	19.1	28.6
Actuarial loss, net of tax of ($81.6), ($90.4), ($19.7), ($23.0)	(34.8)	(40.9)
Total	(15.7)	(12.3)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), Tax Effect	$ (19.7)	$ (23.0)