Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Measurements [Abstract]

Schedule of fair value measurement on a recurring basis

December 31, 2021

	Carrying amount in				Fair Value Measurement Using
	balance sheet		Fair Value		Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents:
Commercial paper	$	1,520	$	1,520	$	1,520	$	0	$	0
Treasury Bills		5,000		5,000		5,000		0		0
Treasury Bills - maturity date greater than three months		3,000		3,000		3,000		0		0
Equity securities		56		56		0		0		56

December 31, 2020

	Carrying amount in				Fair Value Measurement Using
	balance sheet		Fair Value		Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents:
Commercial paper	$	718	$	718	$	718	$	0	$	0
Treasury Bills		7,999		7,999		7,999		0		0
Equity securities		42		42		0		0		42

Summary of changes in level 3 assets at fair value on a recurring basis

	Years Ended December 31,
	2021		2020
Beginning Balance	$	42	$	45
Change in value		14		(3	)
Ending Balance	$	56	$	42