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				111
AspenTech purchases of common stock					$ (56)
Purchases								(2,000)		$ (44)
Net earnings common stockholders	$ 12,475					12,475
Dividends paid (per share: $0.52, $0.525, $1.56 and $1.575, respectively)						(904)			(1)
Foreign currency translation	437						432
Pension and postretirement	(23)						(23)
Cash flow hedges	4						4
Issued under stock plans								61
Net earnings (loss)									(13)
Stock plans									79
Climate Technologies divestiture									(29)
Other comprehensive income	418								5
Stockholders' equity, ending balance at Jun. 30, 2023	26,413	$ 20,464	477	112		39,624	(1,072)	(18,677)	5,949
Stockholders' equity, beginning balance at Mar. 31, 2023			477	138		30,571	(1,148)	(18,678)	5,987
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock plans				30
AspenTech purchases of common stock					(56)
Purchases								0		(44)
Net earnings common stockholders	9,352					9,352
Dividends paid (per share: $0.52, $0.525, $1.56 and $1.575, respectively)						(299)			(1)
Foreign currency translation	86						85
Pension and postretirement	10						10
Cash flow hedges	(19)						(19)
Issued under stock plans								1
Net earnings (loss)									14
Stock plans									21
Climate Technologies divestiture									(29)
Other comprehensive income	77								1
Stockholders' equity, ending balance at Jun. 30, 2023	26,413	20,464	477	112		39,624	(1,072)	(18,677)	5,949
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				186
AspenTech purchases of common stock					(108)
Purchases								(175)		(80)
Net earnings common stockholders	972					972
Dividends paid (per share: $0.52, $0.525, $1.56 and $1.575, respectively)						(907)			(3)
Foreign currency translation	56						56
Pension and postretirement	(36)						(36)
Cash flow hedges	(4)						(4)
Issued under stock plans								126
Net earnings (loss)									15
Stock plans									48
Climate Technologies divestiture									0
Other comprehensive income	16								0
Stockholders' equity, ending balance at Jun. 30, 2024	26,688	20,799	477	140		40,135	(1,237)	(18,716)	5,889
Stockholders' equity, beginning balance at Mar. 31, 2024			477	158		40,108	(1,097)	(18,746)	5,881
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock plans				16
AspenTech purchases of common stock					$ (34)
Purchases								0		$ (25)
Net earnings common stockholders	329					329
Dividends paid (per share: $0.52, $0.525, $1.56 and $1.575, respectively)						(302)			(3)
Foreign currency translation	(124)						(122)
Pension and postretirement	(12)						(12)
Cash flow hedges	(6)						(6)
Issued under stock plans								30
Net earnings (loss)									23
Stock plans									15
Climate Technologies divestiture									0
Other comprehensive income	(142)								(2)
Stockholders' equity, ending balance at Jun. 30, 2024	$ 26,688	$ 20,799	$ 477	$ 140		$ 40,135	$ (1,237)	$ (18,716)	$ 5,889