Organization Of Business	3 Months Ended
Mar. 31, 2021
Organization Of Business [Abstract]
Organization Of Business	1. Organization of Business Interactive Brokers Group, Inc. (“IBG, Inc.”) is a Delaware holding company whose primary asset is its ownership of approximately 21.8% of the membership interests of IBG LLC, which, in turn, owns operating subsidiaries (collectively, “IBG LLC”). IBG, Inc. together with IBG LLC and its consolidated subsidiaries (collectively, “the Company”), is an automated global electronic broker specializing in executing and clearing trades in stocks, options, futures, foreign exchange instruments, bonds, mutual funds and exchange traded funds (“ETFs”) on more than 135 electronic exchanges and market centers around the world and offering custody, prime brokerage, securities and margin lending services to customers. In the United States of America (“U.S.”), the Company conducts its business primarily from its headquarters in Greenwich, Connecticut and from Chicago, Illinois. Abroad, the Company conducts its business through offices located in Canada, the United Kingdom, Ireland, Luxembourg, Switzerland, Hungary, India, China (Hong Kong and Shanghai), Japan, Singapore, and Australia. As of March 31, 2021, the Company had 2,187 employees worldwide. IBG LLC is a Connecticut limited liability company that conducts its business through its significant operating subsidiaries: Interactive Brokers LLC (“IB LLC”); Interactive Brokers Canada Inc. (“IBC”); Interactive Brokers (U.K.) Limited (“IBUK”); Interactive Brokers Ireland Limited (“IBIE”); Interactive Brokers Luxembourg SARL (“IBLUX”); IBKR Financial Services AG (“IBKRFS”); Interactive Brokers Central Europe Zrt. (“IBCE”); Interactive Brokers (India) Private Limited (“IBI”), Interactive Brokers Hong Kong Limited (“IBHK”), Interactive Brokers Securities Japan, Inc. (“IBSJ”), Interactive Brokers Singapore Private Limited ("IBSG"), and Interactive Brokers Australia Pty Limited (“IBA”). Certain of the operating subsidiaries are members of various securities and commodities exchanges in North America, Europe and the Asia/Pacific region and are subject to regulatory capital and other requirements (see Note 15). IB LLC, IBC, IBUK, IBIE, IBLUX, IBCE, IBI, IBHK, IBSJ, IBSG, and IBA carry securities accounts for customers or perform custodial functions relating to customer securities.

Organization Of Business

3 Months Ended

Mar. 31, 2021

1. Organization of Business

Interactive Brokers Group, Inc. (“IBG, Inc.”) is a Delaware holding company whose primary asset is its ownership of approximately 21.8% of the membership interests of IBG LLC, which, in turn, owns operating subsidiaries (collectively, “IBG LLC”). IBG, Inc. together with IBG LLC and its consolidated subsidiaries (collectively, “the Company”), is an automated global electronic broker specializing in executing and clearing trades in stocks, options, futures, foreign exchange instruments, bonds, mutual funds and exchange traded funds (“ETFs”) on more than 135 electronic exchanges and market centers around the world and offering custody, prime brokerage, securities and margin lending services to customers. In the United States of America (“U.S.”), the Company conducts its business primarily from its headquarters in Greenwich, Connecticut and from Chicago, Illinois. Abroad, the Company conducts its business through offices located in Canada, the United Kingdom, Ireland, Luxembourg, Switzerland, Hungary, India, China (Hong Kong and Shanghai), Japan, Singapore, and Australia. As of March 31, 2021, the Company had 2,187 employees worldwide.

IBG LLC is a Connecticut limited liability company that conducts its business through its significant operating subsidiaries: Interactive Brokers LLC (“IB LLC”); Interactive Brokers Canada Inc. (“IBC”); Interactive Brokers (U.K.) Limited (“IBUK”); Interactive Brokers Ireland Limited (“IBIE”); Interactive Brokers Luxembourg SARL (“IBLUX”); IBKR Financial Services AG (“IBKRFS”); Interactive Brokers Central Europe Zrt. (“IBCE”); Interactive Brokers (India) Private Limited (“IBI”), Interactive Brokers Hong Kong Limited (“IBHK”), Interactive Brokers Securities Japan, Inc. (“IBSJ”), Interactive Brokers Singapore Private Limited ("IBSG"), and Interactive Brokers Australia Pty Limited (“IBA”).

Certain of the operating subsidiaries are members of various securities and commodities exchanges in North America, Europe and the Asia/Pacific region and are subject to regulatory capital and other requirements (see Note 15). IB LLC, IBC, IBUK, IBIE, IBLUX, IBCE, IBI, IBHK, IBSJ, IBSG, and IBA carry securities accounts for customers or perform custodial functions relating to customer securities.