Benefits (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Pension Plan, Defined Benefit [Member]	Jun. 30, 2013 Pension Plan, Defined Benefit [Member]	Jun. 30, 2014 Pension Plan, Defined Benefit [Member]	Jun. 30, 2013 Pension Plan, Defined Benefit [Member]	Jun. 30, 2014 Other Postretirement Benefit Plan, Defined Benefit [Member]	Jun. 30, 2013 Other Postretirement Benefit Plan, Defined Benefit [Member]	Jun. 30, 2014 Other Postretirement Benefit Plan, Defined Benefit [Member]	Jun. 30, 2013 Other Postretirement Benefit Plan, Defined Benefit [Member]
Net Periodic Benefit Cost
Service cost			$ 2.3	$ 3.1	$ 5.0	$ 7.3	$ 2.1	$ 2.3	$ 4.3	$ 5.0
Interest cost			17.0	15.1	34.1	30.2	4.4	3.9	8.9	7.8
Expected return on plan assets			(24.6)	(23.9)	(49.3)	(47.9)	(6.0)	(5.3)	(11.9)	(10.6)
Amortization of:
Transition obligation							0	0	0	0
Prior service cost (credit)			0.5	0.6	1.0	1.2	(0.4)	(0.5)	(0.9)	(1.0)
Actuarial loss			9.3	13.6	18.4	27.2	0.4	0.9	0.6	1.8
Net Periodic Benefit Cost			4.5	8.5	9.2	18.0	0.5	1.3	1.0	3.0
Benefits (Textuals) [Abstract]
Pension and Other Postretirement Benefit Contributions	0
Estimated liability of Postemployment benefits	$ 4.2	$ 4.2