Stock-Based Compensation (Schedule Of Stock Option Activity) (Details) $ / shares in Units, shares in Thousands, $ in Millions	9 Months Ended
	Dec. 31, 2019 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	1,375
Options, Granted | shares	4
Options, Exercised | shares	(196)
Options, Forfeited, cancelled or expired | shares	0
Options, Outstanding, Ending Balance | shares	1,183
Options, Vested and expected to vest | shares	1,183
Options, Exercisable | shares	1,183
Weighted-average exercise price of options outstanding, beginning balance | $ / shares	$ 30.63
Weighted-average exercise price of options granted during period | $ / shares	94.92
Weighted-average exercise price of options exercised during the period | $ / shares	30.49
Weighted-average exercise price of options forfeited, cancelled or expired during the period | $ / shares	0
Weighted-average exercise price of options outstanding, ending balance | $ / shares	30.86
Weighted-average exercise price of options vested and expected to vest | $ / shares	30.86
Weighted-average exercise price of options exercisable | $ / shares	$ 30.86
Weighted-average remaining contractual term of options outstanding	4 years 1 month 20 days
Weighted-average remaining contractual term of options vested and expected to vest	4 years 1 month 20 days
Weighted-average remaining contractual term of options exercisable	4 years 1 month 20 days
Aggregate intrinsic value of options outstanding | $	$ 92
Aggregate intrinsic value of options vested and expected to vest | $	92
Aggregate intrinsic value of options exercisable | $	$ 92