Stock-based Compensation and Employee Benefit Plans (Summary of Outstanding and Exercisable Options) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2011	Mar. 31, 2010
Options outstanding, number of shares	12,899	16,131
Options outstanding, weighted-average remaining contractual term, years	5.26
Options outstanding, weighted-average exercise price	$ 31.39	$ 30.28
Options outstanding, potential dilution	3.90%
Options exercisable, number of shares	9,481
Weighted-average exercise price of options exercisable as of March 31, 2011	$ 34.52
Options exercisable, Potential dilution	2.80%
$0.65 - $19.99 [Member]
Range of exercise prices, minimum	$ 0.65
Range of exercise prices, maximum	$ 19.99
Options outstanding, number of shares	3,477
Options outstanding, weighted-average remaining contractual term, years	7.57
Options outstanding, weighted-average exercise price	$ 17.06
Options outstanding, potential dilution	1.00%
Options exercisable, number of shares	1,618
Weighted-average exercise price of options exercisable as of March 31, 2011	$ 16.95
Options exercisable, Potential dilution	0.50%
$20.00 - $39.99 [Member]
Range of exercise prices, minimum	$ 20.00
Range of exercise prices, maximum	$ 39.99
Options outstanding, number of shares	5,479
Options outstanding, weighted-average remaining contractual term, years	4.21
Options outstanding, weighted-average exercise price	$ 24.45
Options outstanding, potential dilution	1.70%
Options exercisable, number of shares	4,353
Weighted-average exercise price of options exercisable as of March 31, 2011	$ 25.31
Options exercisable, Potential dilution	1.30%
$40.00 - $59.99 [Member]
Range of exercise prices, minimum	$ 40.00
Range of exercise prices, maximum	$ 59.99
Options outstanding, number of shares	3,206
Options outstanding, weighted-average remaining contractual term, years	5.07
Options outstanding, weighted-average exercise price	$ 51.15
Options outstanding, potential dilution	1.00%
Options exercisable, number of shares	2,773
Weighted-average exercise price of options exercisable as of March 31, 2011	$ 51.23
Options exercisable, Potential dilution	0.80%
$60.00 - $65.93 [Member]
Range of exercise prices, minimum	$ 60.00
Range of exercise prices, maximum	$ 65.93
Options outstanding, number of shares	737
Options outstanding, weighted-average remaining contractual term, years	2.97
Options outstanding, weighted-average exercise price	$ 64.68
Options outstanding, potential dilution	0.20%
Options exercisable, number of shares	737
Weighted-average exercise price of options exercisable as of March 31, 2011	$ 64.68
Options exercisable, Potential dilution	0.20%