Financial Instruments

6 Months Ended

Sep. 30, 2013

Financial Instruments [Abstract]

Financial Instruments

(3) FINANCIAL INSTRUMENTS

Cash and Cash Equivalents

As of September 30, 2013 and March 31, 2013, our cash and cash equivalents were $1,090 million and $1,292 million, respectively. Cash equivalents were valued at their carrying amounts as they approximate fair value due to the short maturities of these financial instruments.

Short-Term Investments

Short-term investments consisted of the following as of September 30, 2013 and March 31, 2013 (in millions):

	As of September 30, 2013								As of March 31, 2013
	Cost or Amortized Cost		Gross Unrealized				Fair Value		Cost or Amortized Cost		Gross Unrealized				Fair Value
			Gains		Losses						Gains		Losses
Corporate bonds	$	178	$	1	$	—	$	179	$	177	$	1	$	—	$	178
U.S. agency securities	58		—		—		58		76		—		—		76
U.S. Treasury securities	54		—		—		54		85		—		—		85
Commercial paper	37		—		—		37		49		—		—		49
Short-term investments	$	327	$	1	$	—	$	328	$	387	$	1	$	—	$	388

We evaluate our investments for impairment quarterly. Factors considered in the review of investments with an unrealized loss include the credit quality of the issuer, the duration that the fair value has been less than the adjusted cost basis, the severity of the impairment, the reason for the decline in value and potential recovery period, the financial condition and near-term prospects of the investees, our intent to sell and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in market value, and any contractual terms impacting the prepayment or settlement process. Based on our review, we did not consider these investments to be other-than-temporarily impaired as of September 30, 2013 and March 31, 2013.

The following table summarizes the amortized cost and fair value of our short-term investments, classified by stated maturity as of September 30, 2013 and March 31, 2013 (in millions):

	As of September 30, 2013				As of March 31, 2013
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Short-term investments
Due in 1 year or less	$	114	$	114	$	160	$	160
Due in 1-2 years	98		99		126		127
Due in 2-3 years	109		109		101		101
Due in 3-4 years	6		6		—		—
Short-term investments	$	327	$	328	$	387	$	388

0.75% Convertible Senior Notes Due 2016

The following table summarizes the carrying value and fair value of our 0.75% Convertible Senior Notes due 2016 as of September 30, 2013 and March 31, 2013 (in millions):

	As of September 30, 2013				As of March 31, 2013
	Carrying Value		Fair Value		Carrying Value		Fair Value
0.75% Convertible Senior Notes due 2016	$	570	$	692	$	559	$	614

The carrying value of the 0.75% Convertible Senior Notes due 2016 excludes the fair value of the equity conversion feature, which was classified as equity upon issuance, while the fair value is based on quoted market prices for the 0.75% Convertible Senior Notes due 2016, which includes the equity conversion feature. The fair value of the 0.75% Convertible Senior Notes due 2016 is classified as Level 2 within the fair value hierarchy. See Note 12 for additional information related to our 0.75% Convertible Senior Notes due 2016.