Financial Instruments (Tables)

9 Months Ended

Dec. 31, 2017

Financial Instruments [Abstract]

Fair Value Of Short-Term Investments

Short-term investments consisted of the following as of December 31, 2017 and March 31, 2017 (in millions):

	As of December 31, 2017									As of March 31, 2017
	Cost or Amortized Cost		Gross Unrealized					Fair Value		Cost or Amortized Cost		Gross Unrealized					Fair Value
			Gains		Losses							Gains		Losses
Corporate bonds	$	1,212	$	—	$	(3	)	$	1,209	$	944	$	—	$	(1	)	$	943
U.S. Treasury securities	448		—		(2		)	446		414		—		(1		)	413
U.S. agency securities	117		—		(2		)	115		152		—		(1		)	151
Commercial paper	294		—		—			294		212		—		—			212
Foreign government securities	98		—		—			98		113		—		—			113
Asset-backed securities	135		—		(1		)	134		135		—		—			135
Certificates of deposit	22		—		—			22		—		—		—			—
Short-term investments	$	2,326	$	—	$	(8	)	$	2,318	$	1,970	$	—	$	(3	)	$	1,967

Fair Value Of Short-Term Investments By Stated Maturity Date Schedule

The following table summarizes the amortized cost and fair value of our short-term investments, classified by stated maturity as of December 31, 2017 and March 31, 2017 (in millions):

	As of December 31, 2017				As of March 31, 2017
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Short-term investments
Due within 1 year	$	1,598	$	1,596	$	1,237	$	1,236
Due 1 year through 5 years	725		719		721		719
Due after 5 years	3		3		12		12
Short-term investments	$	2,326	$	2,318	$	1,970	$	1,967