Pension and Postretirement Plans Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	$ 209.6	$ 208.8
Pension Plans, Defined Benefit [Member]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Prior service cost recognized: Reclassification adjustments	0.1	4.5
Actruarial loss recognized: Reclassification adjustments	19.4	14.3
Actuarial loss arising during period	(12.5)	(74.2)
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Actuarial loss	22.1
Prior service cost (benefit)	0.2
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	22.3
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (loss), Net Gains (Losses), Net of Tax	(192.5)	(196.8)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), Net of tax	(0.3)	(0.4)
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	(192.8)	(197.2)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Prior service cost recognized: Reclassification adjustments	(13.2)	(13.2)
Actruarial loss recognized: Reclassification adjustments	6.8	6.5
Actuarial loss arising during period	(1.8)	(13.2)
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Actuarial loss	6.6
Prior service cost (benefit)	(13.1)
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	(6.5)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (loss), Net Gains (Losses), Net of Tax	(62.7)	(65.9)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), Net of tax	45.9	54.3
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	$ (16.8)	$ (11.6)