Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year			$ 0.0
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	$ 4.3	$ 4.4	13.0	$ 13.1
Interest Cost	7.9	7.9	23.9	23.7
Expected Return on Plan Assets	(8.2)	(5.9)	(24.7)	(17.6)
Amortization of prior service cost (credit)	0.1	0.0	0.2	0.0
Amortization of net loss	3.3	3.7	9.9	11.0
Net Periodic Benefit Cost	7.4	10.1	22.3	30.2
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	0.7	0.7	2.1	2.1
Interest Cost	0.8	0.8	2.2	2.3
Expected Return on Plan Assets	0.0	0.0	0.0	0.0
Amortization of prior service cost (credit)	(0.2)	(0.2)	(0.5)	(0.5)
Amortization of net loss	0.0	0.0	0.0	0.0
Net Periodic Benefit Cost	$ 1.3	$ 1.3	$ 3.8	$ 3.9