Pension and Postretirement Plans Projected Benefit Obligation (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at December 31,	$ 324.6	$ 336.3
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at January 1,	526.1	506.3
Service cost	5.1	5.2	5.7
Interest Cost	24.8	26.8	29.0
Actuarial loss	60.2	36.6
Benefits paid	(47.0)	(48.8)
Retiree drug subsidy received	0	0
Early retiree subsidy received	0	0
Other	0	0
Benefit obligation at December 31,	569.2	526.1	506.3
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at January 1,	324.0	325.4
Actual return on plan assets	15.4	39.7
Employer contributions	20.1	7.7
Defined Benefit Plan, Gross Prescription Drug Subsidy Receipts Received	0	0
Early Retirement Subsidy Received	0	0
Defined Benefit Plan, Benefits Paid	(47.0)	(48.8)
Fair value of plan assets at December 31,	312.5	324.0	325.4
Unfunded status	(256.7)	(202.1)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at January 1,	163.5	166.1
Service cost	0.3	0.2	0.4
Interest Cost	7.1	8.0	10.3
Actuarial loss	13.8	11.5
Benefits paid	(27.2)	(27.3)
Retiree drug subsidy received	0.7	1.0
Early retiree subsidy received	1.9	0
Other	4.8	4.0
Benefit obligation at December 31,	164.9	163.5	166.1
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at January 1,	12.3	20.9
Actual return on plan assets	0.3	0
Employer contributions	24.1	17.7
Defined Benefit Plan, Gross Prescription Drug Subsidy Receipts Received	0.7	1.0
Early Retirement Subsidy Received	1.9	0
Defined Benefit Plan, Benefits Paid	(27.2)	(27.3)
Fair value of plan assets at December 31,	12.1	12.3	20.9
Unfunded status	$ (152.8)	$ (151.2)