Condensed Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net Loss	$ (381)	$ (340)	$ (180)	$ (119)
Other comprehensive income (loss), net of tax:
Change in unrealized gains on available-for-sale securities	17	42	(25)	55
Reclassification adjustment for realized gains on available-for-sale securities	0	(1)	0	(1)
Change in unrealized losses on derivative instruments	(3)	(1)	(2)	(1)
Reclassification adjustment for realized losses on derivative instruments	1	0	1	2
Foreign currency translation adjustments	19	(22)	2	(16)
Total other comprehensive income (loss), net of tax	34	18	(24)	39
Total comprehensive loss	$ (347)	$ (322)	$ (204)	$ (80)