Commitments, Contingencies And Guarantees	6 Months Ended
Jun. 30, 2014
Commitments, Contingencies And Guarantees [Abstract]
Commitments, Contingencies And Guarantees	11. Commitments, Contingencies and Guarantees In October 2013, a small number of the Company’s brokerage customers had taken relatively large positions in four stocks listed on the Singapore Exchange. In early October, within a very short timeframe, these securities lost over 90% of their value. The customer accounts were margined and fell into deficits totaling $64 million prior to the time the Company took possession of their securities positions. The Company has recognized a cumulative loss of approximately $79.2 million from October 2013 through June 30, 2014. The maximum aggregate loss, which would occur if the securities’ prices all fell to zero and none of the debts were collected, would be approximately $84 million. The Company is currently pursuing the collection of the debts. The ultimate effect of this incident on the Company’s results will depend upon market conditions and the outcome of the Company’s debt collection efforts. Litigation The Company is subject to certain pending and threatened legal actions which arise out of the normal course of business. Litigation is inherently unpredictable, particularly in proceedings where claimants seek substantial or indeterminate damages, or which are in their early stages. IBG, Inc. has not been able to quantify the actual loss or range of loss related to such legal proceedings, the manner in which they will be resolved, the timing of final resolution or the ultimate settlement. Management believes that the resolution of these actions will not have a material effect, if any, on the Company’s business or financial condition, but may have a material impact on the results of operations for a given period. On February 3, 2010, Trading Technologies International, Inc. (“Trading Technologies”) filed a complaint in the United States District Court for the Northern District of Illinois, Eastern Division, against Interactive Brokers Group, Inc., IBG LLC, Holdings, and Interactive Brokers LLC. Thereafter, Trading Technologies dismissed Interactive Brokers Group, Inc. and Holdings from the case, leaving only IBG LLC and Interactive Brokers LLC as defendants (“Defendants”). The operative complaint, as amended, alleges that the Defendants have infringed and continue to infringe twelve U.S. patents held by Trading Technologies. Trading Technologies is seeking, among other things, unspecified damages and injunctive relief. The case is in the early stages and discovery has yet to begin. While it is too early to predict the outcome of the matter, we believe we have meritorious defenses to the allegations made in the complaint and intend to defend ourselves vigorously against them. However, litigation is inherently uncertain and there can be no guarantee that the Company will prevail or that the litigation can be settled on favorable terms. IBG, Inc. accounts for potential losses related to litigation in accordance with ASC 450, Contingencies. As of June 30, 2014 and December 31, 2013, reserves provided for potential losses related to litigation matters were not material. Guarantees Certain of the Operating Companies provide guarantees to securities clearing houses and exchanges which meet the accounting definition of a guarantee under ASC 460, Guarantees. Under standard membership agreements, clearing house and exchange members are required to guarantee collectively the performance of other members. Under the agreements, if a member becomes unable to satisfy its obligations, other members would be required to meet shortfalls. In the opinion of management, the Operating Companies’ liability under these arrangements is not quantifiable and could exceed the cash and securities they have posted as collateral. However, the potential for these Operating Companies to be required to make payments under these arrangements is remote. Accordingly, no contingent liability is carried in the condensed consolidated statements of financial condition for these arrangements. In connection with its retail brokerage business, IB LLC or other electronic brokerage Operating Companies perform securities and commodities execution, clearance and settlement on behalf of their customers for whom they commit to settle trades submitted by such customers with the respective clearing houses. If a customer fails to fulfill its settlement obligations, the respective Operating Company must fulfill those settlement obligations. No contingent liability is carried on the condensed consolidated statements of financial condition for such customer obligations. Other Commitments Certain clearing houses and clearing banks and firms used by certain Operating Companies are given a security interest in certain assets of those Operating Companies held by those clearing organizations. These assets may be applied to satisfy the obligations of those Operating Companies to the respective clearing organizations.

11. Commitments, Contingencies and Guarantees

In October 2013, a small number of the Company’s brokerage customers had taken relatively large positions in four stocks listed on the Singapore Exchange. In early October, within a very short timeframe, these securities lost over 90% of their value. The customer accounts were margined and fell into deficits totaling $64 million prior to the time the Company took possession of their securities positions. The Company has recognized a cumulative loss of approximately $79.2 million from October 2013 through June 30, 2014. The maximum aggregate loss, which would occur if the securities’ prices all fell to zero and none of the debts were collected, would be approximately $84 million. The Company is currently pursuing the collection of the debts. The ultimate effect of this incident on the Company’s results will depend upon market conditions and the outcome of the Company’s debt collection efforts.

Litigation

The Company is subject to certain pending and threatened legal actions which arise out of the normal course of business. Litigation is inherently unpredictable, particularly in proceedings where claimants seek substantial or indeterminate damages, or which are in their early stages. IBG, Inc. has not been able to quantify the actual loss or range of loss related to such legal proceedings, the manner in which they will be resolved, the timing of final resolution or the ultimate settlement. Management believes that the resolution of these actions will not have a material effect, if any, on the Company’s business or financial condition, but may have a material impact on the results of operations for a given period.

On February 3, 2010, Trading Technologies International, Inc. (“Trading Technologies”) filed a complaint in the United States District Court for the Northern District of Illinois, Eastern Division, against Interactive Brokers Group, Inc., IBG LLC, Holdings, and Interactive Brokers LLC. Thereafter, Trading Technologies dismissed Interactive Brokers Group, Inc. and Holdings from the case, leaving only IBG LLC and Interactive Brokers LLC as defendants (“Defendants”). The operative complaint, as amended, alleges that the Defendants have infringed and continue to infringe twelve U.S. patents held by Trading Technologies. Trading Technologies is seeking, among other things, unspecified damages and injunctive relief. The case is in the early stages and discovery has yet to begin. While it is too early to predict the outcome of the matter, we believe we have meritorious defenses to the allegations made in the complaint and intend to defend ourselves vigorously against them. However, litigation is inherently uncertain and there can be no guarantee that the Company will prevail or that the litigation can be settled on favorable terms.

IBG, Inc. accounts for potential losses related to litigation in accordance with ASC 450, Contingencies. As of June 30, 2014 and December 31, 2013, reserves provided for potential losses related to litigation matters were not material.

Guarantees

Certain of the Operating Companies provide guarantees to securities clearing houses and exchanges which meet the accounting definition of a guarantee under ASC 460, Guarantees. Under standard membership agreements, clearing house and exchange members are required to guarantee collectively the performance of other members. Under the agreements, if a member becomes unable to satisfy its obligations, other members would be required to meet shortfalls. In the opinion of management, the Operating Companies’ liability under these arrangements is not quantifiable and could exceed the cash and securities they have posted as collateral. However, the potential for these Operating Companies to be required to make payments under these arrangements is remote. Accordingly, no contingent liability is carried in the condensed consolidated statements of financial condition for these arrangements.

In connection with its retail brokerage business, IB LLC or other electronic brokerage Operating Companies perform securities and commodities execution, clearance and settlement on behalf of their customers for whom they commit to settle trades submitted by such customers with the respective clearing houses. If a customer fails to fulfill its settlement obligations, the respective Operating Company must fulfill those settlement obligations. No contingent liability is carried on the condensed consolidated statements of financial condition for such customer obligations.

Other Commitments

Certain clearing houses and clearing banks and firms used by certain Operating Companies are given a security interest in certain assets of those Operating Companies held by those clearing organizations. These assets may be applied to satisfy the obligations of those Operating Companies to the respective clearing organizations.