Derivatives 2 (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
Sep. 30, 2012	Mar. 31, 2012
Derivatives, Fair Value [Line Items]
Fair value of interest rate derivative assets	$ 25	$ 27
Net fair value of foreign currency contracts	3	(2)
Derivatives (Textual) [Abstract]
Total value of senior notes subject to fair value interest rate swaps	500
Notional value of purchase and sales contracts for foreign currency contracts outstanding	881	893
Tenure of foreign currency contracts outstanding	less than six months	less than six months
6.125% Notes due December 2014 [Member]
Derivatives, Fair Value [Line Items]
Long-term debt, interest rate	6.125%
Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional amount of fair value hedge instruments	500
Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of interest rate derivative assets	12	11
Fair value of foreign currency contracts included in "Other current assets"	8	2
Other Noncurrent Assets, Net [Member]
Derivatives, Fair Value [Line Items]
Fair value of interest rate derivative assets	13	16
Accrued Expenses and Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of foreign currency contracts included in "Accrued expenses and other current liabilities"	$ 5	$ 4

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Tenure of foreign currency contracts outstanding.

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Total value of Senior Notes subject to fair value interest rate swaps.

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- Definition

Interest rate stated in the contractual debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

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- Definition

Fair value as of the balance sheet date of all foreign currency derivative assets not designated as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 17

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Fair value as of the balance sheet date of all foreign currency derivatives not designated as hedging instruments.

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- Definition

Aggregate notional amount of all derivatives designated as a fair value hedging instrument. The notional amount relates to a number of currency units, shares, bushels, pounds, or other units specified in a derivative instrument.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Notional Amount

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Aggregate notional amount of all foreign currency derivatives not designated as hedging instruments. Notional amount refers to the number of currency units specified in the foreign currency derivative contract.

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