Stock-Based Compensation (Schedule Of Stock Option Activity) (Details) $ / shares in Units, shares in Thousands, $ in Millions	6 Months Ended
	Sep. 30, 2016 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options, Outstanding, Beginning Balance | shares	3,278
Options, Granted | shares	3
Options, Exercised | shares	(318)
Options, Forfeited, cancelled or expired | shares	(31)
Options, Outstanding, Ending Balance | shares	2,932
Options, Vested and expected to vest | shares	2,874
Options, Exercisable | shares	2,337
Weighted-average exercise price of options outstanding, beginning balance | $ / shares	$ 35.09
Weighted-average exercise price of options granted during period | $ / shares	69.77
Weighted-average exercise price of options exercised during the period | $ / shares	30.06
Weighted-average exercise price of options forfeited, cancelled or expired during the period | $ / shares	35.84
Weighted-average exercise price of options outstanding, ending balance | $ / shares	35.66
Weighted-average exercise price of options vested and expected to vest | $ / shares	35.75
Weighted-average exercise price of options exercisable | $ / shares	$ 36.83
Weighted-average remaining contractual term of options outstanding	5 years 14 days
Weighted-average remaining contractual term of options vested and expected to vest	4 years 11 months 25 days
Weighted-average remaining contractual term of options exercisable	4 years 5 months 9 days
Aggregate intrinsic value of options outstanding | $	$ 146
Aggregate intrinsic value of options vested and expected to vest | $	143
Aggregate intrinsic value of options exercisable | $	$ 114