Cover page - shares	9 Months Ended
	Sep. 30, 2022	Oct. 21, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2022
Document Transition Report	false
Entity File Number	000-51280
Entity Registrant Name	MORNINGSTAR, INC.
Entity Central Index Key	0001289419
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Amendment Flag	false
Title of 12(b) Security	Common stock, no par value
Entity Incorporation, State or Country Code	IL
Entity Tax Identification Number	36-3297908
Entity Address, Address Line One	22 West Washington Street
Entity Address, City or Town	Chicago
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60602
Trading Symbol	MORN
Security Exchange Name	NASDAQ
City Area Code	312
Local Phone Number	696-6000
Entity Current Reporting Status	Yes
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		42,446,188