Earnings Per Share (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
Apr. 30, 2016	Apr. 30, 2015
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net earnings	$ 87.5	$ 104.9
Weighted Average Number of Shares Outstanding, Basic	126.1	129.2
Incremental shares based upon the assumed exercise of stock options and unvested restricted stock units	0.4	0.6
Weighted Average Number of Shares Outstanding, Diluted	126.5	129.8
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1.4	0.7

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Antidilution
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-URI http://asc.fasb.org/extlink&oid=6510752

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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-Publisher FASB
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The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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