Earnings Per Share Earnings Per Share (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Apr. 30, 2015	Apr. 30, 2014
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net earnings	$ 104.9us-gaap_NetIncomeLoss	$ 125.6us-gaap_NetIncomeLoss
Basic	129.2	128.9
Incremental shares based upon the assumed exercise of stock options and unvested restricted stock units	0.6	0.9
Weighted Average Number of Shares Outstanding, Diluted	129.8	129.8
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.7	0.3

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

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-Name Accounting Standards Codification

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-Section 50

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

+ References

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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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