Consolidated Statements Of Stockholders' Equity (USD $) In Millions, except Share data in Thousands, unless otherwise specified	Total	Common Stock [Member]	Paid-In Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Income [Member]	Repurchase Program, Total [Member]
Balance at Mar. 31, 2011	$ 2,564	$ 3	$ 2,495	$ (153)	$ 219
Balance (in shares) at Mar. 31, 2011		332,564
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	30			76	(46)
Issuance of common stock	12		12
Issuance of common stock (in shares)		7,850
Equity issued in connection with acquisition	87		87
Equity issued in connection with acquisition (in shares)		4,356
Equity value of convertible note issuance, net	105		105
Purchase of convertible note hedge	(107)		(107)
Sale of common stock warrants	65		65
Repurchase and retirement of common stock	(471)		(471)			(471)
Stock repurchased and retired during period, Shares		(24,547)				25,000
Stock-based compensation	170		170
Tax benefit (costs) from exercise of stock options	3		3
Balance at Mar. 31, 2012	2,458	3	2,359	(77)	173
Balance (in shares) at Mar. 31, 2012		320,223
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	(6)			98	(104)
Issuance of common stock	1		1
Issuance of common stock (in shares)		7,801
Repurchase and retirement of common stock			(349)			349
Stock repurchased and retired during period, Shares		(25,860)				26,000
Stock-based compensation	164		164
Tax benefit (costs) from exercise of stock options	(1)		(1)
Balance at Mar. 31, 2013	2,267	3	2,174	21	69
Balance (in shares) at Mar. 31, 2013	302,000	302,164
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	(24)			8	(32)
Issuance of common stock	16		16
Issuance of common stock (in shares)		9,278
Stock-based compensation	150		150
Tax benefit (costs) from exercise of stock options	13		13
Balance at Mar. 31, 2014	$ 2,422	$ 3	$ 2,353	$ 29	$ 37
Balance (in shares) at Mar. 31, 2014	311,000	311,442