Consolidated Statements of Other Comprehensive Income (Loss) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Net income (loss)	$ 8	$ 98	$ 76
Other comprehensive income (loss), net of tax:
Change in unrealized net gains and losses on available-for-sale securities	0	(46)	(40)
Reclassification adjustment for net realized gains on available-for-sale securities	0	(41)	(2)
Change in unrealized net gains and losses on derivative instruments	(19)	(2)	(4)
Reclassification adjustment for net realized losses on derivative instruments	9	4	4
Foreign currency translation adjustments	(22)	(19)	(4)
Total other comprehensive income (loss), net of tax	(32)	(104)	(46)
Total comprehensive loss	$ (24)	$ (6)	$ 30