v3.25.4

Cover Page Cover - USD ($) $ in Millions	12 Months Ended
Cover Page Cover - USD ($) $ in Millions	Dec. 31, 2025	Feb. 06, 2026	Jun. 30, 2025
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2025
Entity File Number	000-51280
Entity Registrant Name	MORNINGSTAR, INC.
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
City Area Code	312
Local Phone Number	696-6000
Title of 12(b) Security	Common stock, no par value
Trading Symbol	MORN
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 8,300.0
Entity Common Stock, Shares Outstanding		39,583,760
Entity Central Index Key	0001289419
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	FY
Amendment Flag	false
Documents Incorporated by Reference [Text Block]	Certain parts of the registrant's Definitive Proxy Statement for the 2026 Annual Meeting of Shareholders, which will be filed not later than 120 days after the registrant's fiscal year ended December 31, 2025, are incorporated into Part III of this Form 10-K.
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Auditor Firm ID	185
Auditor Location	Chicago, IL
Auditor Name	KPMG LLP
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Morningstar, Inc. 10-K