Pension and Postretirement Benefit Costs (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Pension Plans, Defined Benefit [Member]
Components of net periodic benefit costs
Service cost for benefits earned	$ 0.6	$ 0.5	$ 1.7	$ 1.5
Interest cost on projected benefit obligation	10.6	11.7	31.7	35.1
Expected return on plan assets	(14.9)	(15.9)	(44.6)	(47.8)
Amortization of actuarial loss and prior service cost	16.6	12.4	49.9	37.2
Net periodic pension costs	12.9	8.7	38.7	26.0
Other Postretirement Benefit Plans, Defined Benefit [Member]
Components of net periodic benefit costs
Service cost for benefits earned	4.0	3.6	11.8	10.9
Interest cost on projected benefit obligation	10.5	13.7	31.4	41.2
Amortization of actuarial loss and prior service cost	5.6	8.8	16.8	26.2
Special Termination Benefits	(0.6)	0	0.9	0
Net periodic pension costs	$ 19.5	$ 26.1	$ 60.9	$ 78.3