Stock Plans 4 (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Stock option activity
Number of shares, Outstanding beginning balance	3.7	6.0	5.8
Weighted average exercise price, Outstanding beginning balance (in dollars per share)	$ 26.13	$ 25.17	$ 23.52
Number of shares, Granted	0.9	1.7	1.8
Weighted average exercise price, Granted (in dollars per share)	$ 29.13	$ 27.86	$ 24.39
Number of shares, Exercised	(0.9)	(3.5)	(1.2)
Weighted average exercise price, Exercised (in dollars per share)	$ 25.46	$ 25.06	$ 17.17
Number of shares, Expired or terminated	(0.5)	(0.5)	(0.4)
Weighted average exercise price, Expired or terminated (in dollars per share)	$ 26.81	$ 25.95	$ 22.09
Number of shares, Outstanding ending balance	3.2	3.7	6.0
Weighted average exercise price, Outstanding ending balance (in dollars per share)	$ 27.02	$ 26.13	$ 25.17
Options exercisable
Number of shares, Options exercisable	1.2	0.7	3.7
Weighted average exercise price, Options exercisable (in dollars per share)	$ 25.92	$ 26.07	$ 26.18

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

-Section 50

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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Weighted average price of options that were either forfeited or expired.

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Gross number of share options (or share units) granted during the period.

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No definition available.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Number of share options (or share units) exercised during the current period.

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