Stock-Based Compensation (Schedule Of Stock Option Activity) (Details) $ / shares in Units, shares in Thousands, $ in Millions	9 Months Ended
	Dec. 31, 2020 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	1,074
Options, Granted | shares	2
Options, Exercised | shares	(790)
Options, Forfeited, cancelled or expired | shares	0
Options, Outstanding, Ending Balance | shares	286
Options, Vested and expected to vest | shares	286
Options, Exercisable | shares	286
Weighted-average exercise price of options outstanding, beginning balance | $ / shares	$ 30.85
Weighted-average exercise price of options granted during period | $ / shares	122.84
Weighted-average exercise price of options exercised during the period | $ / shares	29.34
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	35.78
Weighted-average exercise price of options vested and expected to vest | $ / shares	35.78
Weighted-average exercise price of options exercisable | $ / shares	$ 35.78
Weighted-average remaining contractual term of options outstanding	3 years 5 months 26 days
Weighted-average remaining contractual term of options vested and expected to vest	3 years 5 months 26 days
Weighted-average remaining contractual term of options exercisable	3 years 5 months 26 days
Aggregate intrinsic value of options outstanding | $	$ 31
Aggregate intrinsic value of options vested and expected to vest | $	31
Aggregate intrinsic value of options exercisable | $	$ 31