Basis of Presentation and Consolidation and Recently Issued Accounting Standards (Notes)	3 Months Ended
Dec. 31, 2013
Basis of Presentation and Consolidation and Recently Issued Accounting Standards [Abstract]
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	Basis of Presentation and Consolidation and Recently Issued Accounting Standards INTL FCStone Inc., a Delaware corporation, and its consolidated subsidiaries (collectively “INTL” or “the Company”), form a financial services group focused on domestic and select international markets. The Company’s services include comprehensive risk management advisory services for commercial customers; execution of listed futures and options-on-futures contracts on all major commodity exchanges; the sale of structured over-the-counter (“OTC”) products in a wide range of commodities; physical trading and hedging of precious metals and select other commodities; trading of more than 130 foreign currencies; market-making in international equities; debt origination and asset management. The Company provides these services to a diverse group of more than 20,000 accounts, representing approximately 11,000 consolidated customers located throughout the world, including producers, processors and end-users of nearly all widely-traded physical commodities to manage their risks and enhance margins; to commercial counterparties who are end-users of the firm’s products and services; to governmental and non-governmental organizations; and to commercial banks, brokers, institutional investors and major investment banks. Basis of Presentation and Consolidation The accompanying condensed consolidated balance sheet as of September 30, 2013, which has been derived from audited financial statements, and the unaudited interim condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and note disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) have been condensed or omitted pursuant to those rules and regulations. The Company believes that the disclosures made are adequate to make the information presented not misleading. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation of the condensed consolidated financial statements for the interim periods presented have been reflected as required by Rule 10-01 of Regulation S-X. Operating results for interim periods are not necessarily indicative of the results that may be expected for the full year. It is suggested that these interim condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and related notes contained in the Company’s Form 10-K for the fiscal year ended September 30, 2013 filed with the SEC. These condensed consolidated financial statements include the accounts of INTL FCStone Inc. and all other entities in which the Company has a controlling financial interest. All material intercompany transactions and balances have been eliminated in consolidation. The Company’s fiscal year end is September 30, and the fiscal quarters end on December 31, March 31, June 30 and September 30. Unless otherwise stated, all dates refer to fiscal years and fiscal interim periods. The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities as of the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. The most significant of these estimates and assumptions relate to fair value measurements for financial instruments and investments, revenue recognition, the provision for potential losses from bad debts, valuation of inventories, valuation of goodwill and intangible assets, incomes taxes and contingencies. Although these and other estimates and assumptions are based on the best available information, actual results could be materially different from these estimates. Immaterial Correction of an Error in Previously Reported Condensed Consolidated Financial Statements The prior period condensed consolidated income statement has been revised to reflect the immaterial correction of certain intercompany physical sales which were not correctly eliminated from the condensed consolidated income statement, resulting in a gross-up of sales of physical commodities and cost of sales of physical commodities. The impact of the correction of this error was a decrease in total revenues of $166.7 million from $12,719.5 million to $12,552.8 million and a decrease in cost of sales of physical commodities of $166.7 million from $12,593.8 million to $12,427.1 million. These immaterial corrections did not impact operating revenues or net income. Reclassifications Certain amounts previously reported in the condensed consolidated income statements have been reclassified to conform to the current period presentation. The reclassifications were made to change the income statement presentation to provide the users of the financial statements additional information related to the operating results of the Company. These reclassifications include reclassifying transaction-based clearing expenses and introducing broker commissions separately from compensation and other expenses, and as components along with interest expense in arriving at net operating revenues. Additionally, travel and business development expenses were previously included in ‘other’ expense. The reclassifications had no effect on consolidated operating revenues or net income. Recent Accounting Pronouncements On December 16, 2011, the Financial Accounting Standards Board (“FASB”) issued new guidance on the disclosures about offsetting assets and liabilities. The amended guidance limits the scope of balance sheet offsetting to derivatives, repurchase agreements and securities lending transactions to the extent that they are offset in the financial statements or subject to an enforceable master netting arrangement or similar agreement. While the FASB retained the existing offsetting models under U.S. GAAP, the new standard requires disclosures to allow investors to better compare and understand significant quantitative differences in financial statements prepared under U.S. GAAP. The new standard is effective for annual periods beginning on or after January 1, 2013, and interim periods within those annual periods. Retrospective application is required. This guidance is effective for the Company’s fiscal year beginning October 1, 2013. The Company adopted this guidance starting with the current quarter. The adoption of this guidance did not have a material impact on the Company’s disclosures within the notes to its condensed consolidated financial statements. Refer to Note 4 and Note 10 of the notes to the condensed consolidated financial statements for disclosure of assets and liabilities regarding the Company's derivative instruments and repurchase agreements. In February 2013, the FASB issued Accounting Standards Update (“ASU”) No. 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income requiring new disclosures regarding reclassification adjustments from accumulated other comprehensive income (“AOCI”). ASU No. 2013-02 requires disclosure of amounts reclassified out of AOCI by component. In addition, the entity is required to present, either on the face of the statement where net income is presented or the notes, significant amounts reclassified out of AOCI by the respective line items of net income. The Company adopted this guidance starting with the current quarter. The adoption of this guidance did not have a material impact on the presentation of the Company’s condensed consolidated financial statements. In March 2013, the FASB issued ASU No. 2013-05, Parent’s Accounting for the Cumulative Translation Adjustment upon Derecognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in a Foreign Entity, which addresses the accounting for the cumulative translation adjustment when a parent either sells part or all of its investment in a foreign entity or no longer holds a controlling financial interest in a subsidiary or group of assets that is a nonprofit activity or a business within a foreign entity. For public entities, the ASU is effective prospectively for fiscal years, and interim periods, within those years, beginning after December 15, 2013. Early adoption is permitted. The Company expects to adopt this guidance starting with the first quarter of fiscal year 2015. The adoption of this guidance is not expected to have a material impact on the Company’s condensed consolidated financial statements. In July 2013, the FASB issued ASU No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. This ASU provides that an unrecognized tax benefit, or a portion thereof, should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except to the extent that a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available at the reporting date to settle any additional income taxes that would result from disallowance of a tax position, or the tax law does not require the entity to use, and the entity does not intend to use, the deferred tax asset for such purpose, then the unrecognized tax benefit should be presented as a liability. For public entities, the ASU is effective prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2013. The Company expects to adopt this guidance starting with the first quarter of fiscal year 2015. The adoption of ASU 2013-11 is not expected to have a material impact on the Company’s condensed consolidated financial statements.

Basis of Presentation and Consolidation and Recently Issued Accounting Standards

INTL FCStone Inc., a Delaware corporation, and its consolidated subsidiaries (collectively “INTL” or “the Company”), form a financial services group focused on domestic and select international markets. The Company’s services include comprehensive risk management advisory services for commercial customers; execution of listed futures and options-on-futures contracts on all major commodity exchanges; the sale of structured over-the-counter (“OTC”) products in a wide range of commodities; physical trading and hedging of precious metals and select other commodities; trading of more than 130 foreign currencies; market-making in international equities; debt origination and asset management.

The Company provides these services to a diverse group of more than 20,000 accounts, representing approximately 11,000 consolidated customers located throughout the world, including producers, processors and end-users of nearly all widely-traded physical commodities to manage their risks and enhance margins; to commercial counterparties who are end-users of the firm’s products and services; to governmental and non-governmental organizations; and to commercial banks, brokers, institutional investors and major investment banks.

Basis of Presentation and Consolidation

The accompanying condensed consolidated balance sheet as of September 30, 2013, which has been derived from audited financial statements, and the unaudited interim condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and note disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) have been condensed or omitted pursuant to those rules and regulations. The Company believes that the disclosures made are adequate to make the information presented not misleading. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation of the condensed consolidated financial statements for the interim periods presented have been reflected as required by Rule 10-01 of Regulation S-X.

Operating results for interim periods are not necessarily indicative of the results that may be expected for the full year. It is suggested that these interim condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and related notes contained in the Company’s Form 10-K for the fiscal year ended September 30, 2013 filed with the SEC.

These condensed consolidated financial statements include the accounts of INTL FCStone Inc. and all other entities in which the Company has a controlling financial interest. All material intercompany transactions and balances have been eliminated in consolidation.

The Company’s fiscal year end is September 30, and the fiscal quarters end on December 31, March 31, June 30 and September 30. Unless otherwise stated, all dates refer to fiscal years and fiscal interim periods.

The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities as of the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. The most significant of these estimates and assumptions relate to fair value measurements for financial instruments and investments, revenue recognition, the provision for potential losses from bad debts, valuation of inventories, valuation of goodwill and intangible assets, incomes taxes and contingencies. Although these and other estimates and assumptions are based on the best available information, actual results could be materially different from these estimates.

Immaterial Correction of an Error in Previously Reported Condensed Consolidated Financial Statements

The prior period condensed consolidated income statement has been revised to reflect the immaterial correction of certain intercompany physical sales which were not correctly eliminated from the condensed consolidated income statement, resulting in a gross-up of sales of physical commodities and cost of sales of physical commodities. The impact of the correction of this error was a decrease in total revenues of $166.7 million from $12,719.5 million to $12,552.8 million and a decrease in cost of sales of physical commodities of $166.7 million from $12,593.8 million to $12,427.1 million. These immaterial corrections did not impact operating revenues or net income.

Reclassifications

Certain amounts previously reported in the condensed consolidated income statements have been reclassified to conform to the current period presentation. The reclassifications were made to change the income statement presentation to provide the users of the financial statements additional information related to the operating results of the Company. These reclassifications include reclassifying transaction-based clearing expenses and introducing broker commissions separately from compensation and other expenses, and as components along with interest expense in arriving at net operating revenues. Additionally, travel and business development expenses were previously included in ‘other’ expense. The reclassifications had no effect on consolidated operating revenues or net income.

Recent Accounting Pronouncements

On December 16, 2011, the Financial Accounting Standards Board (“FASB”) issued new guidance on the disclosures about offsetting assets and liabilities. The amended guidance limits the scope of balance sheet offsetting to derivatives, repurchase agreements and securities lending transactions to the extent that they are offset in the financial statements or subject to an enforceable master netting arrangement or similar agreement. While the FASB retained the existing offsetting models under U.S. GAAP, the new standard requires disclosures to allow investors to better compare and understand significant quantitative differences in financial statements prepared under U.S. GAAP. The new standard is effective for annual periods beginning on or after January 1, 2013, and interim periods within those annual periods. Retrospective application is required. This guidance is effective for the Company’s fiscal year beginning October 1, 2013. The Company adopted this guidance starting with the current quarter. The adoption of this guidance did not have a material impact on the Company’s disclosures within the notes to its condensed consolidated financial statements. Refer to Note 4 and Note 10 of the notes to the condensed consolidated financial statements for disclosure of assets and liabilities regarding the Company's derivative instruments and repurchase agreements.

In February 2013, the FASB issued Accounting Standards Update (“ASU”) No. 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income requiring new disclosures regarding reclassification adjustments from accumulated other comprehensive income (“AOCI”). ASU No. 2013-02 requires disclosure of amounts reclassified out of AOCI by component. In addition, the entity is required to present, either on the face of the statement where net income is presented or the notes, significant amounts reclassified out of AOCI by the respective line items of net income. The Company adopted this guidance starting with the current quarter. The adoption of this guidance did not have a material impact on the presentation of the Company’s condensed consolidated financial statements.

In March 2013, the FASB issued ASU No. 2013-05, Parent’s Accounting for the Cumulative Translation Adjustment upon Derecognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in a Foreign Entity, which addresses the accounting for the cumulative translation adjustment when a parent either sells part or all of its investment in a foreign entity or no longer holds a controlling financial interest in a subsidiary or group of assets that is a nonprofit activity or a business within a foreign entity. For public entities, the ASU is effective prospectively for fiscal years, and interim periods, within those years, beginning after December 15, 2013. Early adoption is permitted. The Company expects to adopt this guidance starting with the first quarter of fiscal year 2015. The adoption of this guidance is not expected to have a material impact on the Company’s condensed consolidated financial statements.

In July 2013, the FASB issued ASU No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. This ASU provides that an unrecognized tax benefit, or a portion thereof, should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except to the extent that a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available at the reporting date to settle any additional income taxes that would result from disallowance of a tax position, or the tax law does not require the entity to use, and the entity does not intend to use, the deferred tax asset for such purpose, then the unrecognized tax benefit should be presented as a liability. For public entities, the ASU is effective prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2013. The Company expects to adopt this guidance starting with the first quarter of fiscal year 2015. The adoption of ASU 2013-11 is not expected to have a material impact on the Company’s condensed consolidated financial statements.