Pension and Other Postretirement Benefits (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended		6 Months Ended
	Jul. 28, 2017	Apr. 30, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Payment for Pension Benefits					$ 6.0	$ 0.0
Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated pension plan contributions in current year			$ 44.1		44.1
Payment for Pension Benefits		$ 6.0
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year			60.0		60.0
Defined Benefit Plans, Estimated Future Employer Contributions, Year Two			75.0		75.0
Net periodic benefit cost (income) [Abstract]
Service cost			0.7	$ 0.6	1.4	1.3
Interest cost			27.0	32.0	54.0	64.0
Expected return on assets			(37.5)	(42.8)	(75.1)	(85.7)
Amortization of prior service cost (credit)			1.1	1.3	2.3	2.6
Amortization of (gain) loss			2.7	7.0	5.4	14.0
Net periodic benefit cost (income)			(6.0)	(1.9)	(12.0)	(3.8)
Other Postretirement Benefits [Member]
Net periodic benefit cost (income) [Abstract]
Service cost			1.1	1.2	2.3	2.4
Interest cost			4.4	4.9	8.7	9.9
Amortization of prior service cost (credit)			(14.7)	(15.1)	(29.3)	(30.2)
Amortization of (gain) loss			(1.0)	(1.0)	(2.1)	(2.1)
Net periodic benefit cost (income)			$ (10.2)	$ (10.0)	$ (20.4)	$ (20.0)
Subsequent Event [Member] | Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Payment for Pension Benefits	$ 6.0