Consolidated Statement of Equity Statement - USD ($) $ in Millions	Total	AspenTech	Common stock	Additional paid-in-capital	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock	Noncontrolling interests in subsidiaries
Beginning balance at Sep. 30, 2021				$ 522	$ 26,047	$ (872)	$ (16,291)	$ 40
Statement [Roll Forward]
Stock plans				42
Net earnings common stockholders	$ 896				896
Dividends paid (per share: $0.52 and $0.515, respectively)					(307)
Foreign currency translation	(72)					(72)
Pension and postretirement	(18)					18
Cash flow hedges	4					4
Purchases							(258)
Issued under stock plans							43
Net earnings								(1)
Stock compensation								0
Other comprehensive income	(50)							0
Ending balance at Dec. 31, 2021	10,288		$ 477	564	26,636	(922)	(16,506)	39
Beginning balance at Sep. 30, 2021				522	26,047	(872)	(16,291)	40
Statement [Roll Forward]
Adjustments to Additional Paid in Capital, Other		$ 550
Ending balance at Sep. 30, 2022	16,316			57	28,053	(1,485)	(16,738)	5,952
Statement [Roll Forward]
Common stockholders' equity	10,249
Common stockholders' equity	10,364
Stock plans				55
Net earnings common stockholders	2,331				2,331
Dividends paid (per share: $0.52 and $0.515, respectively)					(308)
Foreign currency translation	241					236
Pension and postretirement	16					(16)
Cash flow hedges	10					10
Purchases							(2,000)
Issued under stock plans							55
Net earnings								(5)
Stock compensation								35
Other comprehensive income	235							5
Ending balance at Dec. 31, 2022	16,714		$ 477	$ 112	$ 30,076	$ (1,255)	$ (18,683)	$ 5,987
Statement [Roll Forward]
Common stockholders' equity	$ 10,727