Pension Benefits and Postretirement Benefits Other Than Pensions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost on Benefits Earned	$ 2.6	$ 2.6	$ 8.2	$ 7.7
Interest Cost on Projected Benefit Obiligation	5.6	5.7	16.8	17.2
Expected Return on Plan Assets	(7.4)	(6.1)	(22.3)	(18.3)
Amortization of Accumulated Unrecognized Actuarial Loss (Gain)	4.7	2.3	14.1	7.0
Total Expense Recognized	5.5	4.5	16.8	13.6
Postretirement Benefits Other than Pensions [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost on Benefits Earned	0.1	0	0.2	0.1
Interest Cost on Projected Benefit Obiligation	0.4	0.5	1.2	1.4
Amortization of Accumulated Unrecognized Actuarial Loss (Gain)	(0.3)	(0.2)	(0.9)	(0.5)
Total Expense Recognized	$ 0.2	$ 0.3	$ 0.5	$ 1.0