Cash and Cash Equivalents and Investments in Marketable Securities (Tables)

12 Months Ended

Mar. 31, 2021

Marketable Securities [Abstract]

Summary of Investments in Marketable Securities

Investments in marketable securities consisted of the following:

	March 31, 2021
	Amortized		Unrealized		Unrealized			Fair
	cost		gains		losses			value
Available-for-sale debt securities:
U.S. government and agency obligations	$	217	$	4	$	(10	)	$	211
Municipal debt securities		8		2		-			10
Commercial paper		196		-		-			196
Corporate debt securities		177		12		(2	)		187
Mortgage-backed securities:
U.S. government agency		31		1		-			32
Non-agency residential		1		-		-			1
Non-agency commercial		47		2		(2	)		47
Asset-backed securities		49		3		-			52
Total available-for-sale debt securities	$	726	$	24	$	(14	)	$	736
Equity investments									4,084
Total investments in marketable securities								$	4,820

	March 31, 2020
	Amortized		Unrealized		Unrealized			Fair
	cost		gains		losses			value
Available-for-sale debt securities:
U.S. government and agency obligations	$	160	$	16	$	-		$	176
Municipal debt securities		9		2		-			11
Certificates of deposit		250		-		(1	)		249
Commercial paper		604		-		(3	)		601
Corporate debt securities		188		10		(1	)		197
Mortgage-backed securities:
U.S. government agency		47		2		-			49
Non-agency residential		1		-		-			1
Non-agency commercial		47		-		(2	)		45
Asset-backed securities		75		-		(3	)		72
Total available-for-sale debt securities	$	1,381	$	30	$	(10	)	$	1,401
Equity investments									2,419
Total investments in marketable securities								$	3,820

Schedule of Gains and Losses on Investments in Marketable Securities Presented in Our Consolidated Statement of Income

The following table represents gains and losses on our investments in marketable securities presented in our Consolidated Statements of Income:

	Years ended March 31,
	2021		2020			2019
Available-for-sale debt securities:
Realized gains (losses)	$	20	$	9		$	(12	)
Other-than-temporary impairment			$	(8	)	$	-
Equity investments:
Unrealized gains recognized	$	114	$	41		$	14
Realized gains on sales	$	15	$	5		$	-

Summary of Contractual Maturities of Available-For-Sale Debt Securities

The amortized cost and fair value by contractual maturities of available-for-sale debt securities are summarized in the following table.  Actual maturities may differ from contractual maturities because certain borrowers have the right to call or prepay certain obligations.

	March 31, 2021
	Amortized cost		Fair value
Available-for-sale debt securities:
Due within 1 year	$	232	$	232
Due after 1 year through 5 years		133		139
Due after 5 years through 10 years		153		156
Due after 10 years		80		77
Mortgage-backed and asset-backed securities 1		128		132
Total	$	726	$	736

¹

Mortgage-backed and asset-backed securities are shown separately from other maturity groupings as these securities have multiple maturity dates.