CONSOLIDATED STATEMENT OF SHAREHOLDER'S EQUITY (USD $) In Millions	Total	Capital stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Retained earnings [Member]
Balance at Mar. 31, 2010	$ 5,273	$ 915	$ 1	$ 104	$ 4,253
Net income	839	0	0	0	839
Net unrealized (loss) gain on available-for-sale marketable securities, net of tax	35	0	0	35	0
Reclassification adjustment for net loss (gain) included in net income, net of tax	5	0	0	5	0
Total comprehensive income	879	0	0	40	839
Stock-based compensation	0
Dividends	(266)	0	0	0	(266)
Balance at Sep. 30, 2010	5,886	915	1	144	4,826
Balance at Mar. 31, 2011	6,856	915	1	100	5,840
Net income	916	0	0	0	916
Net unrealized (loss) gain on available-for-sale marketable securities, net of tax	(21)	0	0	(21)	0
Reclassification adjustment for net loss (gain) included in net income, net of tax	15	0	0	15	0
Total comprehensive income	910	0	0	(6)	916
Stock-based compensation	1	0	1	0	0
Dividends	(741)	0	0	0	(741)
Balance at Sep. 30, 2011	$ 7,026	$ 915	$ 2	$ 94	$ 6,015