Pension Plans and Other Postretirement Benefits (Details8) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive income (loss), net of tax, Total	$ (932.6)	$ (655.5)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost (credit)	(17.2)	(26.2)
Defined Benefit Plan Accumulated Other Comprehensive Income Net Gains Losses Before Tax	(1,326.1)	(943.6)
Defined Benefit Plan Accumulated other comprehensive loss, Total	1,343.3	969.8	1,035.2
Deferred tax effect	(508.7)	(369.6)
Accumulated other comprehensive income (loss), net of tax, Total	(834.6)	(600.2)
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost (credit)	27.7	49.4
Defined Benefit Plan Accumulated Other Comprehensive Income Net Gains Losses Before Tax	(186.3)	(139.4)
Defined Benefit Plan Accumulated other comprehensive loss, Total	158.6	90.0	66.6
Deferred tax effect	(60.6)	(34.7)
Accumulated other comprehensive income (loss), net of tax, Total	$ (98.0)	$ (55.3)