Documentation and Entity Information - USD ($)	12 Months Ended
Documentation and Entity Information - USD ($)	Dec. 31, 2025	Feb. 23, 2026	Jun. 30, 2025
Document Type	10-K/A
Document Period End Date	Dec. 31, 2025
Document Transition Report	false
Entity File Number	001-33440
Entity Registrant Name	INTERACTIVE BROKERS GROUP, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	30-0390693
Entity Address, Address Line One	One Pickwick Plaza
Entity Address, City or Town	Greenwich
Entity Address, State or Province	CT
Entity Address, Postal Zip Code	06830
City Area Code	203
Local Phone Number	618-5800
Title of 12(b) Security	Common Stock, par value $.01 per share
Trading Symbol	IBKR
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Document Annual Report	true
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Emerging Growth Company	false
Entity Public Float			$ 23,755,862,670
Entity Shell Company	false
Documents Incorporated by Reference [Text Block]	Documents Incorporated by Reference: Portions of Registrant’s definitive proxy statement for its 2026 annual meeting of shareholders are incorporated by reference in Part III of this Form 10-K.
Current Fiscal Year End Date	--12-31
Fiscal Period Focus	FY
Document Fiscal Year Focus	2025
Entity Central Index Key	0001381197
Amendment Flag	true
Amendment Description	This Amendment No. 1 (this "Amendment") to the Annual Report on Form 10-K filed on February 27, 2026 (the "Original Annual Report") of Interactive Brokers Group, Inc. (the "Company") is being filed solely for the purpose of correcting a clerical error under the caption "Item 9A. Controls and Procedures" of the Original Annual Report. Under the second paragraph of the "Opinion on Internal Control over Financial Reporting" section in the Report of Independent Registered Public Accounting Firm, the opinion date of the Company's financial statements was incorrectly disclosed as February 26, 2026. The correct date is February 27, 2026. A revised Report of Independent Registered Public Accounting Firm related to Internal Controls over Financial Reporting is included in this Amendment. Except as described above, no other changes have been made to the Original Annual Report. We have not updated the disclosures contained therein to reflect any events which occurred at a date subsequent to the filing of the Original Annual Report.The Company has included as exhibits to this Amendment updated certifications from the Company's Principal Executive Officer and Principal Financial Officer pursuant to Sections 302 and 906 of the Sarbanes-Oxley Act.
Common Class A [Member]
Common Stock Shares Outstanding		445,439,458
Common Class B [Member]
Common Stock Shares Outstanding		400

Interactive Brokers Group, Inc. 10-K/A