Stock-Based Compensation (Schedule Of Stock Option Activity) (Details) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Jun. 30, 2017 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	2,377
Options, Granted | shares	1
Options, Exercised | shares	(736)
Options, Forfeited, cancelled or expired | shares	(2)
Options, Outstanding, Ending Balance | shares	1,640
Options, Vested and expected to vest | shares	1,640
Options, Exercisable | shares	1,452
Weighted-average exercise price of options outstanding, beginning balance | $ / shares	$ 33.35
Weighted-average exercise price of options granted during period | $ / shares	94.79
Weighted-average exercise price of options exercised during the period | $ / shares	40.56
Weighted-average exercise price of options forfeited, cancelled or expired during the period | $ / shares	47.06
Weighted-average exercise price of options outstanding, ending balance | $ / shares	30.15
Weighted-average exercise price of options vested and expected to vest | $ / shares	30.15
Weighted-average exercise price of options exercisable | $ / shares	$ 30.14
Weighted-average remaining contractual term of options outstanding	6 years 1 month 20 days
Weighted-average remaining contractual term of options vested and expected to vest	6 years 1 month 20 days
Weighted-average remaining contractual term of options exercisable	6 years 30 days
Aggregate intrinsic value of options outstanding | $	$ 124
Aggregate intrinsic value of options vested and expected to vest | $	124
Aggregate intrinsic value of options exercisable | $	$ 110