Document and Entity Information - shares	6 Months Ended
	Mar. 31, 2022	May 12, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Document Transition Report	false
Entity File Number	333-262106
Entity Registrant Name	Emersub CX, Inc.
Entity Central Index Key	0001897982
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	87-3100817
Entity Address, Address Line One	8000 W. Florissant Ave.
Entity Address, City or Town	St. Louis
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	63136
City Area Code	314
Local Phone Number	553-2000
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	true
Entity Common Stock, Shares Outstanding		1,000