Variable Interest Entities - JIGPC Joint Venture (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2023	Sep. 30, 2023
Jazan Integrated Gasification and Power Company ("JIGPC")
Schedule of Equity Method Investments [Line Items]
Ownership interest percentage		55.00%
Investment balance		$ 2,828.3	$ 2,862.2
Jazan Integrated Gasification and Power Company ("JIGPC") | Non- controlling Interests
Schedule of Equity Method Investments [Line Items]
Ownership percentage attributable to noncontrolling partner (in percent)		4.00%
Jazan Integrated Gasification and Power Company ("JIGPC") | Aramco
Schedule of Equity Method Investments [Line Items]
Term of project agreement (in years)	25 years