Pension and Other Post-Retirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Defined Benefit Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1.6	$ 1.6	$ 3.0	$ 3.4
Interest cost	5.3	4.6	10.4	9.2
Expected return on plan assets	(7.1)	(6.9)	(14.3)	(13.8)
Unrecognized prior service credit	(0.3)	(0.2)	(0.5)	(0.5)
Unrecognized net actuarial loss (gain)	3.1	4.0	5.7	7.5
Net expense	2.6	3.1	4.3	5.8
Retiree Health and Life [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.1	0	0.1	0.1
Interest cost	0.4	0.4	0.8	0.8
Expected return on plan assets	0	0	0	0
Unrecognized prior service credit	(0.1)	(0.1)	(0.1)	(0.1)
Unrecognized net actuarial loss (gain)	(0.1)	(0.1)	(0.1)	0
Net expense	$ 0.3	$ 0.2	$ 0.7	$ 0.8