Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2012	Mar. 31, 2012
Receivables, allowances	$ 284	$ 252
Interest rate percentage on convertible senior notes, due 2016	0.75%	0.75%
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10	10
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,000	1,000
Common stock, shares issued	301	320
Common stock, shares outstanding	301	320