Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common stockholders' equity	Common stock	Additional paid-in-capital	Additional paid-in-capital AspenTech	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock	Noncontrolling interests in subsidiaries	Noncontrolling interests in subsidiaries AspenTech
Stockholders' equity, beginning balance at Sep. 30, 2022			$ 477	$ 57		$ 28,053	$ (1,485)	$ (16,738)	$ 5,952
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock plans				55
AspenTech purchases of common stock					$ 0
Purchases								(2,000)		$ 0
Net earnings common stockholders	$ 2,331					2,331
Dividends paid (per share: $0.52 and $0.525, respectively)						(308)
Foreign currency translation	241						236
Pension and postretirement	(16)						(16)
Cash flow hedges	10						10
Issued under stock plans								55
Net earnings (loss)									(5)
Stock plans									35
Other comprehensive income	235								5
Stockholders' equity, ending balance at Dec. 31, 2022	16,714	$ 10,727	477	112		30,076	(1,255)	(18,683)	5,987
Stockholders' equity, beginning balance at Sep. 30, 2023	26,598		477	62		40,070	(1,253)	(18,667)	5,909
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock plans				119
AspenTech purchases of common stock					$ (41)
Purchases								(175)		$ (31)
Net earnings common stockholders	142					142
Dividends paid (per share: $0.52 and $0.525, respectively)						(302)
Foreign currency translation	174						172
Pension and postretirement	(12)						(12)
Cash flow hedges	3						3
Issued under stock plans								79
Net earnings (loss)									(10)
Stock plans									11
Other comprehensive income	165								2
Stockholders' equity, ending balance at Dec. 31, 2023	$ 26,555	$ 20,674	$ 477	$ 140		$ 39,910	$ (1,090)	$ (18,763)	$ 5,881