Pension and Other Post-Retirement Benefits (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Defined Benefit Pension [Member]
Components of pension and other post retirement benefit costs
Service cost	$ 1.6		$ 1.5		$ 3.4		$ 3.0
Interest cost	4.6		5.0		9.2		9.9
Expected return on plan assets	(6.9)		(7.4)		(13.8)		(14.8)
Amortization of unrecognized prior service credit	(0.2)	[1]	(0.2)	[1]	(0.5)	[1]	(0.5)	[1]
Amortization of unrecognized net actuarial loss (gains)	4.0	[1]	2.5	[1]	7.5	[1]	5.0	[1]
Net costs	3.1		1.4		5.8		2.6
Retiree Health and Life [Member]
Components of pension and other post retirement benefit costs
Service cost	0		0		0.1		0.1
Interest cost	0.4		0.5		0.8		1.0
Expected return on plan assets	0		0		0		0
Amortization of unrecognized prior service credit	(0.1)	[1]	(0.1)	[1]	(0.1)	[1]	(0.1)	[1]
Amortization of unrecognized net actuarial loss (gains)	(0.1)	[1]	(0.1)	[1]	0	[1]	(0.1)	[1]
Net costs	$ 0.2		$ 0.3		$ 0.8		$ 0.9

[1] (a)Amounts are reclassified from accumulated other comprehensive loss.