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				$ 57		$ 28,053	$ (1,485)	$ (16,738)	$ 5,952
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock plans				127
AspenTech purchases of common stock					$ (122)
Purchase of noncontrolling interests				0					3
Settlement of AspenTech share awards				0
Reclass negative APIC to retained earnings				0		0
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
Purchases								(2,000)		$ (92)
Issued under Emerson stock plans								71
Net earnings									(19)
Stock plans									94
Other comprehensive income	233								1
AspenTech acquisition										0
Climate Technologies divestiture									(29)
Stockholders' equity, ending balance at Sep. 30, 2023	26,598	$ 20,689	$ 477	62		40,070	(1,253)	(18,667)	5,909
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock plans				226
AspenTech purchases of common stock					(119)
Purchase of noncontrolling interests				0					0
Settlement of AspenTech share awards				0
Reclass negative APIC to retained earnings				0		0
Net earnings common stockholders	1,968					1,968
Dividends paid						(1,208)			(2)
Foreign currency translation	400						396
Pension and postretirement	2						2
Cash flow hedges	(13)						(13)
Purchases								(435)		(89)
Issued under Emerson stock plans								130
Net earnings									(13)
Stock plans									64
Other comprehensive income	389								4
AspenTech acquisition										0
Climate Technologies divestiture									0
Stockholders' equity, ending balance at Sep. 30, 2024	27,509	21,636	477	169		40,830	(868)	(18,972)	5,873
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock plans				71
AspenTech purchases of common stock					$ 0
Purchase of noncontrolling interests				(1,400)					(5,832)
Settlement of AspenTech share awards				(76)
Reclass negative APIC to retained earnings				1,321		(1,321)
Net earnings common stockholders	2,293					2,293
Dividends paid						(1,199)			(3)
Foreign currency translation	47						51
Pension and postretirement	(24)						(24)
Cash flow hedges	20						20
Purchases								(1,178)		0
Issued under Emerson stock plans								88
Net earnings									(47)
Stock plans									29
Other comprehensive income	43								(4)
AspenTech acquisition										$ 0
Climate Technologies divestiture									0
Stockholders' equity, ending balance at Sep. 30, 2025	$ 20,298	$ 20,282	$ 477	$ 85		$ 40,603	$ (821)	$ (20,062)	$ 16