Financial Instruments
 6 Months Ended
Sep. 30, 2016
Financial Instruments [Abstract]  
Financial Instruments
(3) FINANCIAL INSTRUMENTS
Cash and Cash Equivalents
As of September 30, 2016 and March 31, 2016, our cash and cash equivalents were $1,746 million and $2,493 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, 2016 and March 31, 2016 (in millions): 
 
As of September 30, 2016
 
As of March 31, 2016
 
Cost or
Amortized
Cost
 
Gross Unrealized
 
Fair
Value
 
Cost or
Amortized
Cost
 
Gross Unrealized
 
Fair
Value
 
Gains
 
Losses
 
Gains
 
Losses
 
Corporate bonds
$
738

 
$
1

 
$
—

 
$
739

 
$
620

 
$
1

 
$
—

 
$
621

U.S. Treasury securities
378

 
1

 
—

 
379

 
389

 
1

 
—

 
390

U.S. agency securities
154

 
—

 
—

 
154

 
167

 
—

 
—

 
167

Commercial paper
79

 
—

 
—

 
79

 
50

 
—

 
—

 
50

Foreign government securities

115

 
—

 
—

 
115

 
113

 
—

 
—

 
113

Asset-backed securities
54

 
—

 
—

 
54

 
—

 
—

 
—

 
—

Short-term investments
$
1,518

 
$
2

 
$
—

 
$
1,520

 
$
1,339

 
$
2

 
$
—

 
$
1,341


The following table summarizes the amortized cost and fair value of our short-term investments, classified by stated maturity as of September 30, 2016 and March 31, 2016 (in millions): 
 
As of September 30, 2016
 
As of March 31, 2016
 
Amortized
Cost
 
Fair
Value
 
Amortized
Cost
 
Fair
Value
Short-term investments
 
 
 
 
 
 
 
Due in 1 year or less
$
749

 
$
749

 
$
571

 
$
571

Due in 1-2 years
415

 
416

 
461

 
462

Due in 2-3 years
295

 
296

 
295

 
296

Due in 3-4 years
59

 
59

 
12

 
12

Short-term investments
$
1,518

 
$
1,520

 
$
1,339

 
$
1,341