Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common stockholders' equity	Common stock	Additional paid-in-capital	Additional paid-in-capital AspenTech	Retained earnings	Retained earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated other comprehensive income (loss)	Treasury stock	Noncontrolling interests in subsidiaries	Noncontrolling interests in subsidiaries AspenTech
Stockholders' equity, beginning balance at Sep. 30, 2020				$ 470		$ 24,955		$ (1,577)	$ (15,920)	$ 42
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock plans				52
AspenTech purchases of common stock					$ 0
Treasury stock, purchases									(500)		$ 0
AspenTech acquisition					0						0
Purchase of noncontrolling interests										0
Net earnings common stockholders	$ 2,303					2,303
Dividends paid						(1,210)				(25)
Foreign currency translation	81							82
Pension and postretirement	605							605
Cash flow hedges	18							18
Issued under Emerson stock plans									129
Net earnings										24
Stock plans	(224)									0
Other comprehensive income	704									(1)
Climate Technologies divestiture										0
Stockholders' equity, ending balance at Sep. 30, 2021	9,923	$ 9,883	$ 477	522		26,047	$ (1)	(872)	(16,291)	40
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock plans				85
AspenTech purchases of common stock					0
Treasury stock, purchases									(500)		0
AspenTech acquisition					(550)						5,890
Purchase of noncontrolling interests										0
Net earnings common stockholders	3,231					3,231
Dividends paid						(1,225)				(4)
Foreign currency translation	(644)							(636)
Pension and postretirement	37							37
Cash flow hedges	(14)							(14)
Issued under Emerson stock plans									53
Net earnings										(1)
Stock plans	(144)									35
Other comprehensive income	(621)									(8)
Climate Technologies divestiture										0
Stockholders' equity, ending balance at Sep. 30, 2022	16,316	10,364	477	57		28,053	0	(1,485)	(16,738)	5,952
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock plans				127
AspenTech purchases of common stock					(122)
Treasury stock, purchases									(2,000)		(92)
AspenTech acquisition					$ 0						$ 0
Purchase of noncontrolling interests										3
Net earnings common stockholders	13,219					13,219
Dividends paid						(1,202)				(1)
Foreign currency translation	254							253
Pension and postretirement	(25)							(25)
Cash flow hedges	4							4
Issued under Emerson stock plans									71
Net earnings										(19)
Stock plans	(271)									94
Other comprehensive income	233									1
Climate Technologies divestiture										(29)
Stockholders' equity, ending balance at Sep. 30, 2023	$ 26,598	$ 20,689	$ 477	$ 62		$ 40,070	$ 0	$ (1,253)	$ (18,667)	$ 5,909