Pension and Other Postretirement Benefits (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended		7 Months Ended
	Jul. 31, 2015	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Jul. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension plan contributions				$ 1.0	$ 112.4
Pension Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension plan contributions				1.0
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year				0.0
Defined Benefit Plans, Estimated Future Employer Contributions, Year Two		$ 0.0		0.0
Net periodic benefit cost (income) [Abstract]
Service cost		0.5	$ 0.3	1.1	0.7
Interest cost		32.5	36.3	65.0	73.0
Expected return on assets		(49.7)	(50.7)	(99.4)	(101.4)
Amortization of prior service cost (credit)		1.1	1.1	2.2	2.1
Amortization of (gain) loss		7.8	0.6	15.6	0.1
Net periodic benefit cost (income)		(7.8)	(12.4)	(15.5)	(25.5)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Net periodic benefit cost (income) [Abstract]
Service cost		1.8	1.0	3.6	2.0
Interest cost		5.6	5.1	11.2	10.1
Amortization of prior service cost (credit)		(16.1)	(18.3)	(32.3)	(36.6)
Amortization of (gain) loss		0.4	(0.4)	0.8	(0.7)
Net periodic benefit cost (income)		$ (8.3)	$ (12.6)	$ (16.7)	$ (25.2)
Subsequent Event [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension plan contributions	$ 23.1					$ 24.1