Employee Benefit Plans Amounts Recognized in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	Jan. 31, 2016	Jan. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 180.1	$ 311.2
Prior service cost (credit)	0.8	0.9
Total before tax	180.9	312.1
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	10.4	32.4
Prior service cost (credit)	(3.0)	(3.7)
Total before tax	$ 7.4	$ 28.7