Pension and Postretirement Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Reduction to postretirement liability	$ 26.1
Reduction to pension liability		10.3
Capitalized portion of defined benefit contribution percent				12.00%	8.00%
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Curtailment gain	0		0	(0.6)	0
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				39.9
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	0.3		0.7	1.7	2.0
Interest cost on projected benefit obligation	4.7		5.3	14.1	16.0
Expected return on plan assets	(6.3)		(6.6)	(19.2)	(19.6)
Curtailment gain		(0.6)		(0.6)	0
Amortization of:
Prior service cost (benefit)	0.1		0	0.2	0.1
Actuarial loss	5.4		4.8	16.4	14.5
Total amortization	5.5		4.8	16.6	14.6
Benefit costs	4.2		4.2	12.6	13.0
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year						18
Pension and Other Postretirement Benefit Contributions				13.3
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	0.1		0.2	0.3	0.4
Interest cost on projected benefit obligation	1.0		1.4	3.0	4.2
Expected return on plan assets	0		0	0	0
Curtailment gain				0	0
Amortization of:
Prior service cost (benefit)	(3.7)		(3.2)	(10.2)	(9.8)
Actuarial loss	1.4		1.6	4.3	5.0
Total amortization	(2.3)		(1.6)	(5.9)	(4.8)
Benefit costs	$ (1.2)		$ 0	$ (2.6)	$ (0.2)