Financial Instruments	6 Months Ended
Sep. 30, 2011
Financial Instruments
Financial Instruments	10. Financial Instruments At September 30, 2011 and March 31, 2011, the carrying amounts of cash and cash equivalents, restricted cash, marketable securities, receivables, drafts and accounts payable and other current liabilities approximated their estimated fair values because of the short maturity of these financial instruments. All highly liquid debt instruments purchased with original maturity of three months or less at the date of acquisition are included in cash and cash equivalents. Included in cash and cash equivalents at September 30, 2011 and March 31, 2011 were money market fund investments of $2.2 billion and $1.7 billion, which are reported at fair value. The fair value of these investments was determined by using quoted prices for identical investments in active markets, which are considered to be Level 1 inputs under the fair value measurements and disclosure guidance. The carrying value of all other cash equivalents approximates their fair value due to their relatively short-term nature. The carrying amounts and estimated fair values of our long-term debt and other financing were $4.0 billion and $4.6 billion at September 30, 2011 and $4.0 billion and $4.3 billion at March 31, 2011. The estimated fair value of our long-term debt and other financing was determined using quoted market prices and other inputs that were derived from available market information. These are considered to be Level 2 inputs under the fair value measurements and disclosure guidance, and may not be representative of actual values that could have been realized or that will be realized in the future.

Financial Instruments

6 Months Ended

Sep. 30, 2011

10. Financial Instruments

At September 30, 2011 and March 31, 2011, the carrying amounts of cash and cash equivalents, restricted cash, marketable securities, receivables, drafts and accounts payable and other current liabilities approximated their estimated fair values because of the short maturity of these financial instruments. All highly liquid debt instruments purchased with original maturity of three months or less at the date of acquisition are included in cash and cash equivalents. Included in cash and cash equivalents at September 30, 2011 and March 31, 2011 were money market fund investments of $2.2 billion and $1.7 billion, which are reported at fair value. The fair value of these investments was determined by using quoted prices for identical investments in active markets, which are considered to be Level 1 inputs under the fair value measurements and disclosure guidance. The carrying value of all other cash equivalents approximates their fair value due to their relatively short-term nature.

The carrying amounts and estimated fair values of our long-term debt and other financing were $4.0 billion and $4.6 billion at September 30, 2011 and $4.0 billion and $4.3 billion at March 31, 2011. The estimated fair value of our long-term debt and other financing was determined using quoted market prices and other inputs that were derived from available market information. These are considered to be Level 2 inputs under the fair value measurements and disclosure guidance, and may not be representative of actual values that could have been realized or that will be realized in the future.