Fair Value Measurements 3 (Details) (USD $) In Millions	Sep. 30, 2011	Mar. 31, 2011
Money Market Funds [Member] \| Cash and Cash Equivalents [Member]
Fair Value Measurements (Details Textual) [Abstract]
Investments	$ 745	$ 1,959
Money Market Funds [Member] \| Other Noncurrent Assets, Net [Member]
Fair Value Measurements (Details Textual) [Abstract]
Investments	50	50
Accrued expenses and other current liabilities [Member]
Fair Value Measurements (Details Textual) [Abstract]
Fair value of facilities abandonment reserve	12	15
Other Noncurrent Liabilities [Member]
Fair Value Measurements (Details Textual) [Abstract]
Fair value of facilities abandonment reserve	$ 33	$ 37

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents investment securities as of the balance sheet date which may include marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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