(Schedule Of Stock Option Activity) (Details) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Mar. 31, 2017 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options, Outstanding, Beginning Balance | shares	3,278
Options, Granted | shares	6
Options, Exercised | shares	(876)
Options, forfeited, cancelled or expired | shares	(31)
Options, Outstanding, Ending Balance | shares	2,377
Options, vested and expected to vest | shares	2,358
Options, Exercisable | shares	1,903
Weighted-average exercise price of options outstanding, beginning balance | $ / shares	$ 35.09
Weighted-average exercise price of options granted during period | $ / shares	74.93
Weighted-Average Exercise Prices, Exercised during period | $ / shares	40.04
Weighted-Average Exercise Prices, Forfeited, cancelled or expired during period | $ / shares	35.75
Weighted-average exercise price of options outstanding, ending balance | $ / shares	33.35
Weighted-average exercise price of options vested and expected to vest | $ / shares	33.38
Weighted-average exercise prices of options exercisable | $ / shares	$ 33.61
Weighted-average remaining contractual term of options outstanding	5 years 3 months 18 days
Weighted-average remaining contractual term of options vested and expected to vest	5 years 3 months 16 days
Weighted-average remaining contractual term of options exercisable	4 years 10 months 16 days
Aggregate intrinsic value of options outstanding | $	$ 134
Aggregate intrinsic value of options vested and expected to vest | $	132
Aggregate intrinsic value of options exercisable | $	$ 106