Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2021

Fair Value Measurements [Abstract]

Schedule of fair value measurement on a recurring basis

September 30, 2021

	Carrying amount				Fair Value Measurement Using
	in balance sheet		Fair Value		Level 1		Level 2		Level 3
Assets:
Cash equivalents
Commercial paper	$	1,420	$	1,420	$	1,420	$	0	$	0
Treasury bills		3,000		3,000		3,000		0		0
Treasury bills		4,999		4,999		4,999		0		0
Equity Securities		42		42		0		0		42

December 31, 2020

	Carrying amount				Fair Value Measurement Using
	in balance sheet		Fair Value		Level 1		Level 2		Level 3
Assets:
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 change in level 3 assets at fair value on a recurring basis

	Nine Months Ended September 30,
	2021		2020
Beginning Balance	$	42	$	45
Change in Fair Value		0		(3	)
Ending Balance	$	42	$	42