Stock Plans 5 (Details) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Mar. 31, 2016 USD ($) $ / shares shares
Summary of stock option information by exercise price range
Shares, Options outstanding | shares	3.7
Aggregate intrinsic value, Options outstanding | $	$ 11.5
Weighted average remaining contractual life, Options outstanding (in years)	7 years 4 months 24 days
Weighted average exercise price, Options outstanding (in dollars per share)	$ 27.72
Shares, Options exercisable | shares	2.0
Aggregate intrinsic value, Options exercisable | $	$ 9.4
Weighted average remaining contractual life, Options exercisable (in years)	6 years 6 months
Weighted average exercise price, Options exercisable (in dollars per share)	$ 26.16
Exercise Price Range $21.78 - $25.00
Summary of stock option information by exercise price range
Range of exercise prices, Minimum (in dollars per share)	21.78
Range of exercise prices, Maximum (in dollars per share)	$ 25.00
Shares, Options outstanding | shares	0.8
Aggregate intrinsic value, Options outstanding | $	$ 6.0
Weighted average remaining contractual life, Options outstanding (in years)	6 years 1 month 6 days
Weighted average exercise price, Options outstanding (in dollars per share)	$ 23.53
Shares, Options exercisable | shares	0.8
Aggregate intrinsic value, Options exercisable | $	$ 6.0
Weighted average remaining contractual life, Options exercisable (in years)	6 years 1 month 6 days
Weighted average exercise price, Options exercisable (in dollars per share)	$ 23.53
Exercise Price Range $25.01 - $30.00
Summary of stock option information by exercise price range
Range of exercise prices, Minimum (in dollars per share)	25.01
Range of exercise prices, Maximum (in dollars per share)	$ 30.00
Shares, Options outstanding | shares	1.4
Aggregate intrinsic value, Options outstanding | $	$ 4.8
Weighted average remaining contractual life, Options outstanding (in years)	7 years 1 month 6 days
Weighted average exercise price, Options outstanding (in dollars per share)	$ 27.43
Shares, Options exercisable | shares	0.8
Aggregate intrinsic value, Options exercisable | $	$ 3.2
Weighted average remaining contractual life, Options exercisable (in years)	6 years 6 months
Weighted average exercise price, Options exercisable (in dollars per share)	$ 26.96
Exercise Price Range $30.01 - over
Summary of stock option information by exercise price range
Range of exercise prices, Minimum (in dollars per share)	$ 30.01
Shares, Options outstanding | shares	1.5
Aggregate intrinsic value, Options outstanding | $	$ 0.7
Weighted average remaining contractual life, Options outstanding (in years)	8 years 7 months 6 days
Weighted average exercise price, Options outstanding (in dollars per share)	$ 30.37
Shares, Options exercisable | shares	0.4
Aggregate intrinsic value, Options exercisable | $	$ 0.2
Weighted average remaining contractual life, Options exercisable (in years)	7 years 7 months 6 days
Weighted average exercise price, Options exercisable (in dollars per share)	$ 30.23