Stock-Based Compensation (Schedule Of Stock Option Activity) (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	6 Months Ended
	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options, Outstanding, Beginning Balance	5,311
Options, Granted	1,244
Options, Exercised	(291)
Options, Forfeited, cancelled or expired	(210)
Options, Outstanding, Ending Balance	6,054
Options, Vested and expected to vest	5,671
Options, Exercisable	3,744
Weighted-average exercise price of options outstanding, beginning balance	$ 37.43
Weighted-average exercise price of options granted during period	$ 35.75
Weighted-average exercise price of options exercised during the period	$ 20.51
Weighted-average exercise price of options forfeited, cancelled or expired during the period	$ 49.83
Weighted-average exercise price of options outstanding, ending balance	$ 37.47
Weighted-average exercise price of options vested and expected to vest	$ 37.85
Weighted-average exercise price of options exercisable	$ 41.43
Weighted-average remaining contractual term of options outstanding	5 years 4 months 5 days
Weighted-average remaining contractual term of options vested and expected to vest	5 years 0 months 25 days
Weighted-average remaining contractual term of options exercisable	2 years 10 months 5 days
Aggregate intrinsic value of options outstanding	$ 34
Aggregate intrinsic value of options vested and expected to vest	32
Aggregate intrinsic value of options exercisable	$ 22