Financing Arrangement (Schedule Of Interest Expense Related To Notes) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Debt Instruments [Abstract]
Amortization of debt discount	$ 5	$ 5	$ 15	$ 9
Amortization of debt issuance costs	0	0	2	1
Coupon interest expense	1	1	3	2
Other interest expense	1	1	1	1
Total interest expense	$ 7	$ 7	$ 21	$ 13