Pension and Other Postretirement Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Pension [Member]
Components of Net Periodic Benefit Expense [Abstract]
Service Cost	$ 2.5	$ 2.3	$ 5.0	$ 4.6
Interest Cost	6.5	6.6	13.0	13.2
Expected Return on Plan Assets	(8.8)	(8.9)	(17.6)	(17.7)
Amortization of Prior Service Costs	0	0.1	0.1	0.2
Amortization of Net Loss	5.4	4.4	10.7	8.7
Amortization of Transition Obligation	0	0	0	0
Net Periodic Benefit Expense	5.6	4.5	11.2	9.0
Contributions			0	0
Estimated Future Contributions			0
Other Postretirement [Member]
Components of Net Periodic Benefit Expense [Abstract]
Service Cost	1.0	1.1	2.0	2.1
Interest Cost	1.7	2.3	3.4	4.7
Expected Return on Plan Assets	(2.4)	(2.5)	(4.9)	(5.0)
Amortization of Prior Service Costs	(0.7)	(0.5)	(1.3)	(0.9)
Amortization of Net Loss	0.4	1.9	0.8	3.8
Amortization of Transition Obligation	0	0.1	0	0.1
Net Periodic Benefit Expense	0	2.4	0	4.8
Contributions			10.8	0
Estimated Future Contributions			$ 0