Derivative Financial Instruments (Narrative) (Details) (USD $) In Millions	Sep. 30, 2011	Mar. 31, 2011
Nondesignated [Member] \| British Pounds Sterling [Member] \| Balance Sheet Hedging [Member]
Derivative [Line Items]
Notional value of foreign currency sale contracts	$ 9	$ 16
Nondesignated [Member] \| Balance Sheet Hedging [Member]
Derivative [Line Items]
Notional value of foreign currency purchase contracts	12	31
Notional value of foreign currency sale contracts	384	140
Cash Flow Hedging [Member]
Derivative [Line Items]
Notional value of foreign currency purchase contracts	38	40
Notional value of foreign currency sale contracts	72	10
Balance Sheet Hedging [Member]
Derivative [Line Items]
Notional value of foreign currency forward contracts	$ 405	$ 187

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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Notional Amount

-URI http://asc.fasb.org/extlink&oid=6519104

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5579245-113959

Name:	us-gaap_NotionalAmountOfForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant