Pension and Postretirement Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Capitalized portion of defined benefit contribution percent	8.00%
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	$ 32.1
Contributions to pension and postretirement plans	6.1
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service Cost	0.6	1.3
Interest cost on projected benefit obligation	6.1	6.2
Expected return on plan assets	(6.9)	(7.3)
Amortization of:
Prior Service Cost (benefit)	0	0.1
Actuarial loss	3.9	3.6
Benefit costs	3.7	3.9
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	21.6
Contributions to pension and postretirement plans	6.1
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service Cost	0.1	0.1
Interest cost on projected benefit obligation	1.6	1.8
Expected return on plan assets	0	0
Amortization of:
Prior Service Cost (benefit)	(3.3)	(3.3)
Actuarial loss	1.6	1.6
Benefit costs	$ 0	$ 0.2