Income Taxes (Notes)	9 Months Ended
Jun. 30, 2014
Income Taxes [Abstract]
Income Tax Disclosure [Text Block]	Income Taxes In determining the quarterly provision for income taxes, management uses an estimated annual effective tax rate which is based on the expected annual income and statutory tax rates in the various jurisdictions in which it operates. The Company’s effective tax rate differs from the U.S. statutory rate primarily due to state and local taxes, and differing statutory tax rates applied to the income of non-U.S. subsidiaries. The Company records the tax effect of certain discrete items, including the effects of changes in tax laws, tax rates and adjustments with respect to valuation allowances or other unusual or nonrecurring tax adjustments, in the interim period in which they occur, as an addition to, or reduction from, the income tax provision, rather than being included in the estimated effective annual income tax rate. In addition, jurisdictions with a projected loss for the year or a year-to-date loss where no tax benefit can be recognized are excluded from the estimated annual effective income tax rate. The Company is required to assess its deferred tax assets and the need for a valuation allowance at each reporting period. This assessment requires judgment on the part of management with respect to benefits that may be realized. The Company will record a valuation allowance against deferred tax assets when it is considered more likely than not that all or a portion of the deferred tax assets will not be realized. The valuation allowance for deferred tax assets as of June 30, 2014 and September 30, 2013 was $2.3 million. The valuation allowances as of June 30, 2014 and September 30, 2013 were primarily related to U.S. state and local and foreign net operating loss carryforwards that, in the judgment of management, are not more likely than not to be realized. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some or all of the deferred tax assets will not be realized. The Company incurred U.S. federal, state, and local taxable (losses) income for the fiscal years ended September 30, 2013, 2012, and 2011 of $(22.2) million, $(21.2) million, and $22.7 million, respectively. There are no significant differences between actual levels of past taxable income and the results of operations, before income taxes in these jurisdictions. U.S. federal, state, and local taxable losses incurred during the years ended September 30, 2013 and 2012 were attributable to a decrease in exchange-traded and OTC derivative transactional volumes and revenue caused by consecutive droughts in the U.S., as well as losses incurred in the physical base metals business and the continuation of a historically low interest rate environment. During 2013, the Company elected to pursue an exit of its physical base metals business through an orderly liquidation of open positions. Additionally, the Company completed an acquisition of the accounts of Tradewire Securities. Although both the exit of the physical base metals business and the acquisition of the Tradewire Securities accounts are expected to positively affect future levels of taxable income, the expected impact cannot be reliably projected. When evaluating if U.S. federal, state, and local deferred tax assets are realizable, the Company considered deferred tax liabilities of $4.3 million that are scheduled to reverse from 2014 to 2018 and $1.3 million of deferred tax liabilities associated with unrealized gains in securities which the Company could sell, if necessary. Furthermore, the Company considered its ability to implement business and tax planning strategies that would allow the remaining U.S. federal, state, and local deferred tax assets, net of valuation allowances, to be realized within approximately 9 years. Based on the tax planning strategies that are prudent and feasible, management believes that it is more likely than not that the Company will realize the tax benefit of the deferred tax assets, net of the existing valuation allowance, in the future. However, the realization of deferred income taxes is dependent on future events, and changes in estimate in future periods could result in adjustments to the valuation allowance. The income tax expense from continuing operations of $0.3 million and $2.0 million for the three months ended June 30, 2014 and 2013, and income tax expense from continuing operations of $4.4 million and $5.9 million for the nine months ended June 30, 2014 and 2013, respectively, reflect estimated federal, foreign and state taxes. For the three months ended June 30, 2014, the Company’s effective tax rate was 8% compared to 28% for the three months ended June 30, 2013. The effective tax rate is lower due to certain discrete items recognized during the quarter ended June 30, 2014. For the nine months ended June 30, 2014, the Company’s effective tax rate was 24% compared to 26% for the nine months ended June 30, 2013. The Company and its subsidiaries file income tax returns with the U.S. federal jurisdiction and various state and foreign jurisdictions. The Company has open tax years ranging from September 30, 2008 through September 30, 2013 with U.S. federal and state and local taxing authorities. In the U.K., the Company has open tax years ending September 30, 2012 to September 30, 2013. In Brazil, the Company has open tax years ranging from December 31, 2008 through December 31, 2012. In Argentina, the Company has open tax years ranging from December 31, 2006 to September 30, 2013. The Internal Revenue Service commenced an examination of the U.S. income tax return for the fiscal year ended September 30, 2010. The IRS examination was settled in April of 2014 with no adjustments. Additionally, INTL FCStone is under state examinations for various periods, ranging from September 2009 through September 30, 2012. The Company is also under examination in Nigeria for tax years 2006 through 2013.

Income Taxes

In determining the quarterly provision for income taxes, management uses an estimated annual effective tax rate which is based on the expected annual income and statutory tax rates in the various jurisdictions in which it operates. The Company’s effective tax rate differs from the U.S. statutory rate primarily due to state and local taxes, and differing statutory tax rates applied to the income of non-U.S. subsidiaries. The Company records the tax effect of certain discrete items, including the effects of changes in tax laws, tax rates and adjustments with respect to valuation allowances or other unusual or nonrecurring tax adjustments, in the interim period in which they occur, as an addition to, or reduction from, the income tax provision, rather than being included in the estimated effective annual income tax rate. In addition, jurisdictions with a projected loss for the year or a year-to-date loss where no tax benefit can be recognized are excluded from the estimated annual effective income tax rate.

The Company is required to assess its deferred tax assets and the need for a valuation allowance at each reporting period. This assessment requires judgment on the part of management with respect to benefits that may be realized. The Company will record a valuation allowance against deferred tax assets when it is considered more likely than not that all or a portion of the deferred tax assets will not be realized.

The valuation allowance for deferred tax assets as of June 30, 2014 and September 30, 2013 was $2.3 million. The valuation allowances as of June 30, 2014 and September 30, 2013 were primarily related to U.S. state and local and foreign net operating loss carryforwards that, in the judgment of management, are not more likely than not to be realized. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some or all of the deferred tax assets will not be realized.

The Company incurred U.S. federal, state, and local taxable (losses) income for the fiscal years ended September 30, 2013, 2012, and 2011 of $(22.2) million, $(21.2) million, and $22.7 million, respectively. There are no significant differences between actual levels of past taxable income and the results of operations, before income taxes in these jurisdictions. U.S. federal, state, and local taxable losses incurred during the years ended September 30, 2013 and 2012 were attributable to a decrease in exchange-traded and OTC derivative transactional volumes and revenue caused by consecutive droughts in the U.S., as well as losses incurred in the physical base metals business and the continuation of a historically low interest rate environment. During 2013, the Company elected to pursue an exit of its physical base metals business through an orderly liquidation of open positions. Additionally, the Company completed an acquisition of the accounts of Tradewire Securities. Although both the exit of the physical base metals business and the acquisition of the Tradewire Securities accounts are expected to positively affect future levels of taxable income, the expected impact cannot be reliably projected. When evaluating if U.S. federal, state, and local deferred tax assets are realizable, the Company considered deferred tax liabilities of $4.3 million that are scheduled to reverse from 2014 to 2018 and $1.3 million of deferred tax liabilities associated with unrealized gains in securities which the Company could sell, if necessary. Furthermore, the Company considered its ability to implement business and tax planning strategies that would allow the remaining U.S. federal, state, and local deferred tax assets, net of valuation allowances, to be realized within approximately 9 years. Based on the tax planning strategies that are prudent and feasible, management believes that it is more likely than not that the Company will realize the tax benefit of the deferred tax assets, net of the existing valuation allowance, in the future. However, the realization of deferred income taxes is dependent on future events, and changes in estimate in future periods could result in adjustments to the valuation allowance.

The income tax expense from continuing operations of $0.3 million and $2.0 million for the three months ended June 30, 2014 and 2013, and income tax expense from continuing operations of $4.4 million and $5.9 million for the nine months ended June 30, 2014 and 2013, respectively, reflect estimated federal, foreign and state taxes.

For the three months ended June 30, 2014, the Company’s effective tax rate was 8% compared to 28% for the three months ended June 30, 2013. The effective tax rate is lower due to certain discrete items recognized during the quarter ended June 30, 2014. For the nine months ended June 30, 2014, the Company’s effective tax rate was 24% compared to 26% for the nine months ended June 30, 2013.

The Company and its subsidiaries file income tax returns with the U.S. federal jurisdiction and various state and foreign jurisdictions. The Company has open tax years ranging from September 30, 2008 through September 30, 2013 with U.S. federal and state and local taxing authorities. In the U.K., the Company has open tax years ending September 30, 2012 to September 30, 2013. In Brazil, the Company has open tax years ranging from December 31, 2008 through December 31, 2012. In Argentina, the Company has open tax years ranging from December 31, 2006 to September 30, 2013. The Internal Revenue Service commenced an examination of the U.S. income tax return for the fiscal year ended September 30, 2010. The IRS examination was settled in April of 2014 with no adjustments. Additionally, INTL FCStone is under state examinations for various periods, ranging from September 2009 through September 30, 2012. The Company is also under examination in Nigeria for tax years 2006 through 2013.