Pension and Postretirement Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Defined Benefit Plan Disclosure [Line Items]
Capitalized portion of defined benefit contribution percent	8.00%		8.00%
Amortization of:
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	$ 0	$ 4.2	$ 0	$ 4.2
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	32		32
Contributions to pension and postretirement plans			12.6
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service Cost	0.7	1.3	1.3	2.6
Interest cost on projected benefit obligation	4.6	6.2	10.7	12.4
Expected return on plan assets	(6.1)	(7.3)	(13.0)	(14.6)
Amortization of:
Prior Service Cost (benefit)	0.1	0.1	0.1	0.2
Defined Benefit Plan, Amortization of Gains (Losses)	5.8	3.5	9.7	7.1
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	4.2	0	4.2
Benefit costs	5.1	8.0	8.8	11.9
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	22		22
Pension and Other Postretirement Benefit Contributions			11.4
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service Cost	0.1	0.1	0.2	0.2
Interest cost on projected benefit obligation	1.2	1.8	2.8	3.6
Expected return on plan assets	0	0	0	0
Amortization of:
Prior Service Cost (benefit)	(3.3)	(3.3)	(6.6)	(6.6)
Defined Benefit Plan, Amortization of Gains (Losses)	1.8	1.6	3.4	3.2
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	0	0	0
Benefit costs	$ (0.2)	$ 0.2	$ (0.2)	$ 0.4