Pension and Postretirement Plans Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
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	$ 4.5	$ 0.5
Actruarial loss recognized: Reclassification adjustments	14.3	9.3
Actuarial loss arising during period	(74.2)	(27.1)
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Actuarial loss	19.9
Prior service cost (benefit)	0.1
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	20.0
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)	(13.1)
Actruarial loss recognized: Reclassification adjustments	6.5	5.2
Actuarial loss arising during period	(13.2)	(11.9)
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)	(13.2)
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	$ (6.6)