Fair Value Measurements (Tables)

3 Months Ended

Jun. 30, 2017

Fair Value Disclosures [Abstract]

Schedule of the Carrying Value of Assets Measured at Fair Value on a Recurring Basis

The following table summarizes our assets measured at fair value on a recurring basis, by level, within the fair value hierarchy:

	June 30, 2017						March 31, 2017
(In millions)	Fair Value		Cash and Cash Equivalents		Short-Term Investments		Fair Value		Cash and Cash Equivalents		Short-Term Investments
Cash	$	480	$	480	$	—	$	1,183	$	1,183	$	—
Non-negotiable certificates of deposit	39		39		—		15		15		—
Level 1 (Quoted prices in active markets for identical assets):
Money market	1,298		1,298		—		2,532		2,532		—
U.S. government securities	102		102		—		94		94		—
Marketable equity securities	8		—		8		9		—		9
Total level 1	1,408		1,400		8		2,635		2,626		9
Level 2 (Significant other observable inputs):
U.S. agency securities	64		64		—		75		75		—
Commercial paper	323		323		—		348		348		—
Total level 2	387		387		—		423		423		—
Total	$	2,314	$	2,306	$	8	$	4,256	$	4,247	$	9