Pension and Postretirement Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Capitalized portion of defined benefit contribution percent	10.00%
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	$ 44
Pension and Other Postretirement Benefit Contributions	3.9
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service Cost	0.6	0.6
Interest cost on projected benefit obligation	5.2	6.1
Expected return on plan assets	(6.1)	(6.9)
Amortization of:
Prior service cost (benefit)	0	0
Actuarial loss	6.0	3.9
Total amortization	6.0	3.9
Benefit costs	5.7	3.7
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
Pension and Other Postretirement Benefit Contributions	4.4
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service Cost	0.1	0.1
Interest cost on projected benefit obligation	1.3	1.6
Expected return on plan assets	0	0
Amortization of:
Prior service cost (benefit)	(3.2)	(3.3)
Actuarial loss	1.6	1.6
Total amortization	(1.6)	(1.7)
Benefit costs	$ (0.2)	$ 0