Commitments and Contingencies Environmental Matter (Details) $ in Millions	12 Months Ended
	Jan. 31, 2018 USD ($)
Environmental Matter Disclosure [Line Items]
Estimated Remediation Costs CPG Preferred Approach Low Estimate	$ 483.0
Identified Remediation Plan, Cost Estimated by the EPA	1,380.0
RoD Design Phase, Settlement Amount by Third Party	$ 165.0