Derivatives 1 (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Other expenses (gains), net [Member] | Foreign Exchange Contract [Member]
Effect of interest rate and foreign exchange derivatives on Consolidated Statement of Operations
Amount of Net (Gain)/Loss Recognized in the Consolidated Statement of Operations	$ (3)	$ 14	$ 20
Cash Flow Hedging [Member] | Interest Expense [Member] | Interest Rate Swap [Member]
Effect of interest rate and foreign exchange derivatives on Consolidated Statement of Operations
Amount of Net (Gain)/Loss Recognized in the Consolidated Statement of Operations	0	4	6
Fair Value Hedging [Member] | Interest Expense [Member] | Interest Rate Swap [Member]
Effect of interest rate and foreign exchange derivatives on Consolidated Statement of Operations
Amount of Net (Gain)/Loss Recognized in the Consolidated Statement of Operations	$ (12)	$ (12)	$ (1)