Pension Benefits - Components Of Comprehensive OPEB (Income) Expense (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Unrecognized Pension Loss Arising During the Year	$ 29.4	$ 53.9	$ 27.9
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Recognized in Net Periodic Benefit Cost, before Tax	(16.2)	(8.7)	(1.2)
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost Earned During the Year	10.8	10.2	9.0
Interest Cost on Projected Benefit Obligation	22.4	22.9	22.4
Expected Return on Plan Assets	(29.8)	(24.4)	(23.7)
Net Amortization and Deferral	18.8	9.4	2.3
Settlement Benefits	0.3	0	0
Pension Expense Recognized	22.5	18.1	10.0
Unrecognized Pension Loss Arising During the Year	34.8	52.4	23.6
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Recognized in Net Periodic Benefit Cost, before Tax	(18.8)	(9.4)	(2.3)
Comprehensive Pension Expense	38.5	61.1	31.3
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	23.9
Pension Plans, Defined Benefit [Member] | Segment, Discontinued Operations [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Expense Recognized	$ 0.5	$ 0.6	$ 0.5