Investments (Narrative) (Details)	9 Months Ended
	Sep. 30, 2023 Number
Marketable Securities [Line Items]
Number of private companies which entity has investments in common equity securities	2
Minimum [Member]
Marketable Securities [Line Items]
Treasury Bills, term	1 month
Maximum [Member]
Marketable Securities [Line Items]
Treasury Bills, term	3 months