Summary of Accounting Policies (Composition of Options Outstanding and Exercisable) (Details) (USD $)	12 Months Ended
	Mar. 31, 2011
Options vested and expected to vest, Number of Shares Outstanding	52,893,459
Options vested and expected to vest, Weighted Average Remaining Contractual Life (Years)	4.27
Options vested and expected to vest, Weighted Average Exercise Price	$ 7.66
$ 1.94 - $2.26 [Member]
Number of Shares Outstanding, Options Outstanding	14,120,595
Weighted Average Remaining Contractual Life (In Years), Options Outstanding	4.72
Weighted Average Exercise Price, Options Outstanding	$ 2.21
Number of Shares Exercisable, Options Exercisable	4,933,133
Weighted Average Exercise Price, Options Exercisable	$ 2.19
Range of Exercise Prices, upper limit	$ 2.26
Range of Exercise Prices, lower limit	$ 1.94
$ 3.39 - $5.75 [Member]
Number of Shares Outstanding, Options Outstanding	12,506,064
Weighted Average Remaining Contractual Life (In Years), Options Outstanding	5.36
Weighted Average Exercise Price, Options Outstanding	$ 5.55
Number of Shares Exercisable, Options Exercisable	6,506,154
Weighted Average Exercise Price, Options Exercisable	$ 5.56
Range of Exercise Prices, upper limit	$ 5.75
Range of Exercise Prices, lower limit	$ 3.39
$ 5.87 - $7.07 [Member]
Number of Shares Outstanding, Options Outstanding	1,481,659
Weighted Average Remaining Contractual Life (In Years), Options Outstanding	3.86
Weighted Average Exercise Price, Options Outstanding	$ 6.31
Number of Shares Exercisable, Options Exercisable	756,198
Weighted Average Exercise Price, Options Exercisable	$ 5.92
Range of Exercise Prices, upper limit	$ 7.07
Range of Exercise Prices, lower limit	$ 5.87
$ 7.08 - $10.59 [Member]
Number of Shares Outstanding, Options Outstanding	12,623,012
Weighted Average Remaining Contractual Life (In Years), Options Outstanding	3.85
Weighted Average Exercise Price, Options Outstanding	$ 9.64
Number of Shares Exercisable, Options Exercisable	8,855,491
Weighted Average Exercise Price, Options Exercisable	$ 9.69
Range of Exercise Prices, upper limit	$ 10.59
Range of Exercise Prices, lower limit	$ 7.08
$ 10.67 - $11.411 [Member]
Number of Shares Outstanding, Options Outstanding	1,517,458
Weighted Average Remaining Contractual Life (In Years), Options Outstanding	4.84
Weighted Average Exercise Price, Options Outstanding	$ 11.13
Number of Shares Exercisable, Options Exercisable	1,496,925
Weighted Average Exercise Price, Options Exercisable	$ 11.13
Range of Exercise Prices, upper limit	$ 11.41
Range of Exercise Prices, lower limit	$ 10.67
$ 11.53 - $13.98 [Member]
Number of Shares Outstanding, Options Outstanding	8,094,953
Weighted Average Remaining Contractual Life (In Years), Options Outstanding	3.44
Weighted Average Exercise Price, Options Outstanding	$ 12.42
Number of Shares Exercisable, Options Exercisable	8,090,786
Weighted Average Exercise Price, Options Exercisable	$ 12.42
Range of Exercise Prices, upper limit	$ 13.98
Range of Exercise Prices, lower limit	$ 11.53
$ 14.34 - $23.02 [Member]
Number of Shares Outstanding, Options Outstanding	3,598,717
Weighted Average Remaining Contractual Life (In Years), Options Outstanding	2.32
Weighted Average Exercise Price, Options Outstanding	$ 17.09
Number of Shares Exercisable, Options Exercisable	3,598,717
Weighted Average Exercise Price, Options Exercisable	$ 17.09
Range of Exercise Prices, upper limit	$ 23.02
Range of Exercise Prices, lower limit	$ 14.34
$ 1.94 - $23.02 [Member]
Number of Shares Outstanding, Options Outstanding	53,942,458
Weighted Average Remaining Contractual Life (In Years), Options Outstanding	4.29
Weighted Average Exercise Price, Options Outstanding	$ 7.61
Number of Shares Exercisable, Options Exercisable	34,237,404
Weighted Average Exercise Price, Options Exercisable	$ 9.23
Range of Exercise Prices, upper limit	$ 23.02
Range of Exercise Prices, lower limit	$ 1.94