Derivatives 1 (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Interest Rate Swaps [Member] | Cash Flow Hedges [Member] | Interest Expense, Net [Member]
Effect of interest rate and foreign exchange derivatives on Consolidated Statements of Operations
Amount of net (gain)/loss from derivative instruments recognized in the Consolidated Statements of Operations	$ 0	$ 0	$ 4
Interest Rate Swaps [Member] | Fair Value Hedges [Member] | Interest Expense, Net [Member]
Effect of interest rate and foreign exchange derivatives on Consolidated Statements of Operations
Amount of net (gain)/loss from derivative instruments recognized in the Consolidated Statements of Operations	(12)	(12)	(12)
Foreign Currency Contracts [Member] | Other (Gains) Expenses, Net [Member]
Effect of interest rate and foreign exchange derivatives on Consolidated Statements of Operations
Amount of net (gain)/loss from derivative instruments recognized in the Consolidated Statements of Operations	$ 11	$ (3)	$ 14