Financial Instruments And Hedging Activities	12 Months Ended
Mar. 31, 2012
Financial Instruments And Hedging Activities [Abstract]
Financial Instruments And Hedging Activities	16. Financial Instruments and Hedging Activities At March 31, 2012 and 2011, the carrying amounts of cash and cash equivalents, restricted cash, marketable securities, receivables, drafts and accounts payable, short-term borrowings 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 March 31, 2012 and 2011, were money market fund investments of $0.8 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 disclosures guidance. The carrying value of all other cash equivalents approximates fair value due to their relatively short-term nature. The carrying amount and estimated fair value of our long-term debt and other financing was $3.6 billion and $4.1 billion at March 31, 2012 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. In the normal course of business, we are exposed to interest rate changes and foreign currency fluctuations. At times we limit these risks through the use of derivatives such as interest rate swaps and forward foreign exchange contracts. In accordance with our policy, derivatives are only used for hedging purposes. We do not use derivatives for trading or speculative purposes. Foreign currency rate risk The majority of our operations are conducted in US dollars however, certain assets and liabilities, revenues and expense and purchasing activities are incurred in and exposed to other currencies. We have established certain foreign currency rate risk programs that manage the impact of foreign currency fluctuation. These programs are utilized on a transactional basis when we consider there to be a risk in fair value or volatility in cash flows. These programs reduce but do not entirely eliminate foreign currency rate risk. Currently, our foreign currency rate risk programs include: In March 2012, we entered into a number of forward contracts to hedge Canadian dollar denominated cash flows. These contracts mature over a period of eight years and have a gross notional value of $528 million. These contracts have been designated for hedge accounting and accordingly, changes in the contracts' fair value will be recorded to accumulated other comprehensive income and reclassified into earnings in the same period in which the hedged transaction affects earnings. At March 31, 2012, the fair value of these contracts was not material and no amounts were reclassified to earnings in 2012. In 2012, we entered into a number of forward contracts to hedge British pound denominated cash flows. These contracts mature in 2013 and have a gross notional value of $151 million. These contracts have not been designated for hedge accounting and accordingly, changes in these contracts' fair value are recorded directly in earnings. At March 31, 2012, the fair value of these contracts was not material and net gains or losses for the year ended March 31, 2012 were also not material. The fair values of all derivatives 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.

16. Financial Instruments and Hedging Activities

At March 31, 2012 and 2011, the carrying amounts of cash and cash equivalents, restricted cash, marketable securities, receivables, drafts and accounts payable, short-term borrowings 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 March 31, 2012 and 2011, were money market fund investments of $0.8 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 disclosures guidance. The carrying value of all other cash equivalents approximates fair value due to their relatively short-term nature.

The carrying amount and estimated fair value of our long-term debt and other financing was $3.6 billion and $4.1 billion at March 31, 2012 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.

In the normal course of business, we are exposed to interest rate changes and foreign currency fluctuations. At times we limit these risks through the use of derivatives such as interest rate swaps and forward foreign exchange contracts. In accordance with our policy, derivatives are only used for hedging purposes. We do not use derivatives for trading or speculative purposes.

Foreign currency rate risk

The majority of our operations are conducted in US dollars however, certain assets and liabilities, revenues and expense and purchasing activities are incurred in and exposed to other currencies. We have established certain foreign currency rate risk programs that manage the impact of foreign currency fluctuation. These programs are utilized on a transactional basis when we consider there to be a risk in fair value or volatility in cash flows. These programs reduce but do not entirely eliminate foreign currency rate risk. Currently, our foreign currency rate risk programs include:

In March 2012, we entered into a number of forward contracts to hedge Canadian dollar denominated cash flows. These contracts mature over a period of eight years and have a gross notional value of $528 million. These contracts have been designated for hedge accounting and accordingly, changes in the contracts' fair value will be recorded to accumulated other comprehensive income and reclassified into earnings in the same period in which the hedged transaction affects earnings. At March 31, 2012, the fair value of these contracts was not material and no amounts were reclassified to earnings in 2012.

In 2012, we entered into a number of forward contracts to hedge British pound denominated cash flows. These contracts mature in 2013 and have a gross notional value of $151 million. These contracts have not been designated for hedge accounting and accordingly, changes in these contracts' fair value are recorded directly in earnings. At March 31, 2012, the fair value of these contracts was not material and net gains or losses for the year ended March 31, 2012 were also not material.

The fair values of all derivatives 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.