StoneX (SNEX) 10-Q10 Feb 142014 Q1 Quarterly reportFinancial data

Company Profile

DEI

DEI	3 Months Ended
DEI	Dec. 31, 2013	Feb. 07, 2014
Document and Entity Information [Abstract]	'	'
Entity Registrant Name	'INTL FCSTONE INC.	'
Trading Symbol	'INTL	'
Entity Central Index Key	'0000913760	'
Current Fiscal Year End Date	'--09-30	'
Entity Filer Category	'Accelerated Filer	'
Document Type	'10-Q	'
Document Period End Date	31-Dec-13	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Amendment Flag	'false	'
Entity Common Stock, Shares Outstanding	'	19,072,274
Entity Well-known Seasoned Issuer	'No	'
Entity Voluntary Filers	'No	'
Entity Current Reporting Status	'Yes	'

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
ASSETS	'	'
Cash and cash equivalents	$194.90	$156.10
Cash, securities and other assets segregated under federal and other regulations (including $33.5 and $107.6 at fair value at December 31, 2013 and September 30, 2013, respectively)	215	449.4
Deposits and receivables from:	'	'
Exchange-clearing organizations (including $1,353.5 and $1,371.7 at fair value at December 31, 2013 and September 30, 2013, respectively)	1,706.10	1,576.60
Broker-dealers, clearing organizations and counterparties (including $(5.1) and $(13.1) at fair value at December 31, 2013 and September 30, 2013, respectively)	163.9	168.3
Receivables from customers, net	74.6	93.3
Notes receivable, net	46.2	37.4
Income taxes receivable	13.7	15.5
Financial instruments owned, at fair value	169	158.5
Physical commodities inventory	26.6	59
Deferred income taxes, net	28.6	25.5
Property and equipment, net	17.2	17.5
Goodwill and intangible assets, net	58.8	59.1
Other assets	29.3	31.8
Total assets	2,743.90	2,848
Liabilities:	'	'
Accounts payable and other accrued liabilities (including $9.1 and $9.6 at fair value at December 31, 2013 and September 30, 2013, respectively)	98.6	114
Payables to:	'	'
Customers	1,983.10	2,091.80
Broker-dealers, clearing organizations and counterparties	3.6	17
Lenders under loans and overdrafts	60.2	61
Senior Notes	45.5	45.5
Income taxes payable	4.1	3.4
Financial instruments sold, not yet purchased, at fair value	211.4	179.9
Deferred income taxes	0.1	0
Total liabilities	2,406.60	2,512.60
Commitments and contingencies (Note 11)	'	'
Stockholders' Equity:	'	'
Preferred stock, $0.01 par value. Authorized 1,000,000 shares; no shares issued or outstanding	0	0
Common stock, $0.01 par value. Authorized 30,000,000 shares; 19,675,192 issued and 19,182,219 outstanding at December 31, 2013 and 19,638,330 issued and 19,209,157 outstanding at September 30, 2013	0.2	0.2
Common stock in treasury, at cost - 492,973 shares at December 31, 2013 and 429,173 shares at September 30, 2013, respectively	-9.1	-7.8
Additional paid-in capital	225.6	224
Retained earnings	127.9	125.4
Accumulated other comprehensive loss, net	-7.3	-6.4
Total stockholders' equity	337.3	335.4
Total liabilities and equity	$2,743.90	$2,848

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets Parentheticals (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Balance Sheet Parentheticals [Abstract]	'	'
Securities and other assets segregated, fair value	$33.50	$107.60
Dep and rec -exch clear org - fair value	1,353.50	1,371.70
Dep and rec -b/d - fair value	-5.1	-13.1
Accounts payable and other accrued liabilities - contingent consideration, fair value	$9.10	$9.60
Preferred stock - par value	$0.01	$0.01
Preferred stock - authorized	1,000,000	1,000,000
Preferred stock - issued	0	0
Preferred stock - outstanding	0	0
Common stock - par value	$0.01	$0.01
Common stock - authorized	30,000,000	30,000,000
Common stock - issued	19,675,192	19,638,330
Common stock - outstanding	19,182,219	19,209,157
Treasury stock - shares	492,973	429,173

Condensed_Consolidated_Income_

Condensed Consolidated Income Statements (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Revenues:	'	'
Sales of physical commodities	$7,830.30	$12,421.20
Trading gains, net	51.9	79.9
Commission and clearing fees	42.2	40
Consulting and management fees	12	8.3
Interest income	1.4	3.3
Other income	0.2	0.1
Total revenues	7,938	12,552.80
Cost of sales of physical commodities	7,824.60	12,427.10
Operating revenues	113.4	125.7
Transaction-based clearing expenses	25.2	24.6
Introducing broker commissions	11.6	8.4
Interest expense	2.7	3.5
Net operating revenues	73.9	89.2
Compensation and other expenses:	'	'
Compensation and benefits	46.4	46.7
Communication and data services	6.3	5.3
Occupancy and equipment rental	3	2.9
Professional fees	4.4	3.7
Travel and business development	2.8	3
Depreciation and amortization	1.9	1.8
Bad debts and impairments	0.4	0.4
Other	4.7	6.6
Total compensation and other expenses	69.9	70.4
Income from operations, before tax	4	18.8
Income tax expense	1.5	5.5
Net income	$2.50	$13.30
Basic earnings per share:	'	'
Basic net income per common share	$0.13	$0.70
Diluted earnings per share:	'	'
Diluted net income per common share	$0.12	$0.68
Weighted-average number of common shares outstanding:	'	'
Basic weighted-average number of common shares outstanding	18,657,678	18,266,338
Diluted weighted-average number of common shares outstanding	19,358,442	18,778,675

Condensed_Consolidated_Stateme

Condensed Consolidated Statement of Comprehensive Income (USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Condensed Consolidated Statement of Other Comprehensive Income (Loss) [Abstract]	'	'
Net income	$2.50	$13.30
Other comprehensive income (loss), net of tax:	'	'
Foreign currency translation adjustment	-1.2	-0.3
Pension liabilities adjustment	0.1	0.4
Net unrealized gain or loss on available-for-sale securities	0.2	-0.2
Reclassification of adjustment for gains included in net income [Abstract]	'	'
Realized gain on available-for-sale securities (included in trading gains, net)	0	-8.3
Income tax expense from reclassification adjustments (included in income tax expense)	0	2
Reclassification adjustment for gains included in net income	0	-6.3
Other comprehensive loss	-0.9	-6.4
Comprehensive income	$1.60	$6.90

Condensed_Consolidated_Cash_Fl

Condensed Consolidated Cash Flows Statements (USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:	'	'
Net income	$2.50	$13.30
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation and amortization	1.8	1.8
Provision for bad debts and impairments	0.5	0.4
Deferred income taxes	-3.2	-0.4
Amortization of debt issuance costs and debt discount	0.3	0.3
Amortization of stock-based compensation expense	1.1	1.6
Loss on sale of property and equipment	0.2	0
Gain on sale of exchange memberships and common stock	0	-9.2
Changes in operating assets and liabilities, net:	'	'
Cash, securities and other assets segregated under federal and other regulations	233.3	-24.2
Deposits and receivables from exchange-clearing organizations	-129.8	141.1
Deposits and receivables from broker-dealers, clearing organizations, and counterparties	4.8	1.4
Receivable from customers, net	18.3	-75.2
Notes receivable from customers, net	-8.9	13.7
Income taxes receivable	1.6	4.2
Financial instruments owned, at fair value	-11.9	11.6
Physical commodities inventory	32.4	-2.3
Other assets	2.4	-2
Accounts payable and other accrued liabilities	-14.3	-20
Payable to customers	-107.4	-8
Payable to broker-dealers, clearing organizations and counterparties	-13.4	-31.8
Income taxes payable	0.9	0.8
Financial instruments sold, not yet purchased, at fair value	31.4	12.1
Net cash provided by operating activities	42.6	29.2
Cash flows from investing activities:	'	'
Sale of exchange memberships and common stock	0	10.1
Purchase of property and equipment	-1.3	-1.2
Net cash (used in) provided by investing activities	-1.3	8.9
Cash flows from financing activities:	'	'
Net change in payable to lenders under loans	-0.8	23.2
Payments related to earn-outs on acquisitions	-0.3	-0.3
Debt issuance costs	-0.3	0
Exercise of stock options	0.5	0
Share repurchases	-1.3	-2
Income tax expense on stock options and awards	0	-0.3
Net cash (used in) provided by financing activities	-2.2	20.6
Effect of exchange rates on cash and cash equivalents	-0.3	-0.3
Net increase in cash and cash equivalents	38.8	58.4
Cash and cash equivalents at beginning of period	156.1	236.3
Cash and cash equivalents at end of period	194.9	294.7
Supplemental disclosure of cash flow information:	'	'
Cash paid for interest	2.6	2.5
Income taxes paid, net of cash refunds	1.5	1.3
Supplemental disclosure of non-cash investing and financing activities:	'	'
Identified intangible assets and goodwill on acquisitions	0	3.1
Additional consideration payable related to acquisitions	$0.20	$3.40

Condensed_Consolidated_Stateme1

Condensed Consolidated Statement of Stockholders' Equity (USD $)	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]
In Millions, unless otherwise specified	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]
Balances at beginning of period at Sep. 30, 2013	$335.40	$0.20	($7.80)	$224	$125.40	($6.40)
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'
Net income	2.5	'	'	'	2.5	'
Other comprehensive loss	-0.9	'	'	'	'	-0.9
Proceeds from Stock Options Excercised (including income tax benefit)	0.5	'	'	0.5	'	'
Stock-based Compensation	1.1	'	'	1.1	'	'
Repurchase of stock	-1.3	'	-1.3	'	'	'
Balances at end of period at Dec. 31, 2013	$337.30	$0.20	($9.10)	$225.60	$127.90	($7.30)

Basis_of_Presentation_and_Cons

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.

Earnings_per_Share_Notes

Earnings per Share (Notes)	3 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share [Text Block]	'
	Earnings per Share
	The Company presents basic and diluted earnings per share (“EPS”) using the two-class method which requires all outstanding unvested share-based payment awards that contain rights to non-forfeitable dividends and therefore participate in undistributed earnings with common stockholders be included in computing earnings per share. Under the two-class method, net earnings are reduced by the amount of dividends declared in the period for each class of common stock and participating security. The remaining undistributed earnings are then allocated to common stock and participating securities, based on their respective rights to receive dividends. Restricted stock awards granted to certain employees and directors and shares held in trust for the Provident Group acquisition contain non-forfeitable rights to dividends at the same rate as common stock, and are considered participating securities.
	Basic EPS has been computed by dividing net income by the weighted-average number of common shares outstanding. The following is a reconciliation of the numerator and denominator of the diluted net income per share computations for the periods presented below.


		Three Months Ended December 31,
	(in millions, except share amounts)	2013			2012
	Numerator:
	Net income	$	2.5		$	13.3

	Less: Allocation to participating securities	(0.1		)	(0.5		)
	Income from operations allocated to common stockholders	$	2.4		$	12.8

	Diluted net income	$	2.5		$	13.3

	Less: Allocation to participating securities	(0.1		)	(0.5		)
	Diluted net income allocated to common stockholders	$	2.4		$	12.8

	Denominator:
	Weighted average number of:
	Common shares outstanding	18,657,678			18,266,338

	Dilutive potential common shares outstanding:
	Share-based awards	700,764			512,337

	Diluted weighted-average shares	19,358,442			18,778,675

	The dilutive effect of share-based awards is reflected in diluted net income per share by application of the treasury stock method, which includes consideration of unamortized share-based compensation expense required under the Compensation – Stock Compensation Topic of the Accounting Standards Codification (“ASC”).
	Options to purchase 1,126,282 and 1,490,547 shares of common stock for the three months ended December 31, 2013 and 2012, respectively, were excluded from the calculation of diluted earnings per share because they would have been anti-dilutive.

Assets_and_Liabilities_at_Fair

Assets and Liabilities, at Fair Value (Notes)	3 Months Ended
	Dec. 31, 2013
Assets and Liabilities, at Fair Value [Abstract]	'
Fair Value Disclosures [Text Block]	'
	Assets and Liabilities, at Fair Value
	The Company’s financial and nonfinancial assets and liabilities reported at fair value are included in the following captions on the condensed consolidated balance sheets:

	•	Cash and cash equivalents

	•	Cash, securities and other assets segregated under federal and other regulations

	•	Deposits and receivables from exchange-clearing organizations, broker-dealers, clearing organizations and counterparties

	•	Financial instruments owned

	•	Accounts payable and other accrued liabilities

	•	Payables to customers

	•	Payables to broker-dealers, clearing organizations and counterparties

	•	Financial instruments sold, not yet purchased
	Fair Value Hierarchy
	The majority of financial assets and liabilities on the consolidated balance sheets are reported at fair value. Cash is reported at the balance held at financial institutions. Cash equivalents includes money market funds, which are valued at period-end at the net asset value provided by the fund’s administrator, and certificates of deposit, which are stated at cost plus accrued interest, which approximates fair value. Cash, securities and other assets segregated under federal and other regulations include the value of cash collateral as well as the value of other pledged investments, primarily U.S. Treasury bills and obligations issued by government sponsored entities and commodities warehouse receipts. Deposits with and receivables from exchange-clearing organizations and broker-dealers, clearing organizations and counterparties and payable to customers and broker-dealers, clearing organizations and counterparties include the value of cash collateral as well as the value of money market funds and other pledged investments, primarily U.S. Treasury bills and obligations issued by government sponsored entities and mortgage-backed securities. These balances also include the fair value of exchange-traded futures and options-on-futures and exchange-cleared swaps and options determined by prices on the applicable exchange. Financial instruments owned and sold, not yet purchased include the value of U.S. and foreign government obligations, corporate debt securities, derivative financial instruments, commodities and mutual funds. The fair value of exchange common stock is determined by quoted market prices, and the fair value of exchange memberships is determined by recent sale transactions. The carrying value of notes receivable, net approximates fair value, given their short duration. Payables to lenders under loans carry variable rates of interest and thus approximate fair value. The fair value of the Company’s senior unsecured notes is estimated to be $46.2 million (carrying value of $45.5 million) as of December 31, 2013, based on the transaction prices at public exchanges for the same or similar issues.
	The fair value estimates presented in the condensed consolidated financial statements are based on pertinent information available to management as of December 31, 2013 and September 30, 2013. Although management is not aware of any factors that would significantly affect the estimated fair value amounts, such amounts have not been comprehensively revalued for purposes of these condensed consolidated financial statements since that date and current estimates of fair value may differ significantly from the amounts presented in the condensed consolidated financial statements.
	Cash equivalents, securities, commodities warehouse receipts, derivative financial instruments, commodities leases, exchange common stock and contingent liabilities are carried at fair value, on a recurring basis, and are classified and disclosed into three levels in the fair value hierarchy. The Company did not have any fair value adjustments for assets or liabilities measured at fair value on a non-recurring basis during the three months ended December 31, 2013. The three levels of the fair value hierarchy under the Fair Value Measurements and Disclosures Topic of the ASC are:
	Level 1 - Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;
	Level 2 - Quoted prices for identical or similar assets or liabilities in markets that are less active, that is, markets in which there are few transactions for the asset or liability that are observable for substantially the full term; and
	Level 3 - Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).
	The following tables set forth the Company’s financial and nonfinancial assets and liabilities accounted for at fair value, on a recurring basis, as of December 31, 2013 and September 30, 2013 by level in the fair value hierarchy. There were no assets or liabilities that were measured at fair value on a nonrecurring basis as of December 31, 2013 and September 30, 2013.


		December 31, 2013
	(in millions)	Level 1			Level 2			Level 3			Netting and				Total
											Collateral
											-1
	Assets:
	Money market funds	$	0.1		$	—		$	—		$	—			$	0.1

	Certificate of deposits	3			—			—			—				3

	Unrestricted cash equivalents	3.1			—			—			—				3.1

	Commodities warehouse receipts	14.5			—			—			—				14.5

	U.S. government obligations	—			19			—			—				19

	Securities and other assets segregated under federal and other regulations	14.5			19			—			—				33.5

	Money market funds	776.8			—			—			—				776.8

	U.S. government obligations	—			590			—			—				590

	Mortgage-backed securities	—			3.5			—			—				3.5

	Derivatives	1,577.20			—			—			(1,594.0		)		(16.8		)

	Deposits and receivables from exchange-clearing organizations	2,354.00			593.5			—			(1,594.0		)		1,353.50

	Deposits and receivables from broker-dealers, clearing organizations and counterparties - derivatives	0.3			0.9			—			(6.3		)		(5.1		)

	Common and preferred stock and American Depositary Receipts (“ADRs”)	62.3			15.8			0.7			—				78.8

	Exchangeable foreign ordinary equities and ADRs	28.8			—			—			—				28.8

	Corporate and municipal bonds	17.2			—			3.4			—				20.6

U.S. government obligations	—			0.3			—			—				0.3

Foreign government obligations	9.8			—			—			—				9.8

Derivatives	146.4			553.8			—			(681.6		)		18.6

Commodities leases	—			40.4			—			(39.7		)		0.7

Exchange firm common stock	4.7			—			—			—				4.7

Mutual funds and other	5.2			—			—			—				5.2

Mortgage-backed securities	—			1.5			—			—				1.5

Financial instruments owned	274.4			611.8			4.1			(721.3		)		169

Total assets at fair value	$	2,646.30		$	1,225.20		$	4.1		$	(2,321.6	)		$	1,554.00

Liabilities:
Accounts payable and other accrued liabilities - contingent liabilities	$	—		$	—		$	9.1		$	—			$	9.1

Payable to customers - derivatives	1,494.10			—			—			(1,494.1		)		—

Common and preferred stock and ADRs	91.5			11.3			—			—				102.8

Exchangeable foreign ordinary equities and ADRs	15			—			—			—				15

Corporate and municipal bonds	15.7			0.2			—			—				15.9

Derivatives	151.9			542.4			—			(660.0		)		34.3

Commodities leases	—			82.2			—			(38.8		)		43.4

Financial instruments sold, not yet purchased	274.1			636.1			—			(698.8		)		211.4

Total liabilities at fair value	$	1,768.20		$	636.1		$	9.1		$	(2,192.9	)		$	220.5



-1	Represents cash collateral and the impact of netting across the levels of the fair value hierarchy. Netting among positions classified within the same level is included in that level.


	September 30, 2013
(in millions)	Level 1			Level 2			Level 3			Netting and				Total
										Collateral
										-1
Assets:
Money market funds	$	0.1		$	—		$	—		$	—			$	0.1

Certificate of deposits	2.9			—			—			—				2.9

Unrestricted cash equivalents	3			—			—			—				3

Money market funds	75			—			—			—				75

Commodities warehouse receipts	13.1			—			—			—				13.1

U.S. government obligations	—			19.5			—			—				19.5

Securities and other assets segregated under federal and other regulations	88.1			19.5			—			—				107.6

Money market funds	841.4			—			—			—				841.4

U.S. government obligations	—			594.8			—			—				594.8

Mortgage-backed securities	—			5.3			—			—				5.3

Derivatives	2,263.20			—			—			(2,333.0		)		(69.8		)

Deposits and receivables from exchange-clearing organizations	3,104.60			600.1			—			(2,333.0		)		1,371.70

Deposits and receivables from broker-dealers, clearing organizations and counterparties - derivatives	1.8			0.2			—			(15.1		)		(13.1		)

Common and preferred stock and American Depositary Receipts (“ADRs”)	49.3			19.8			0.7			—				69.8

Exchangeable foreign ordinary equities and ADRs	36.7			—			—			—				36.7

Corporate and municipal bonds	0.1			—			3.5			—				3.6

U.S. government obligations	—			0.3			—			—				0.3

Foreign government obligations	7.7			—			—			—				7.7

Derivatives	173.6			440.6			—			(592.3		)		21.9

Commodities leases	—			56.1			—			(50.0		)		6.1

Commodities warehouse receipts	4			—			—			—				4

Exchange firm common stock	4.4			—			—			—				4.4

Mutual funds and other	4			—			—			—				4

Financial instruments owned	279.8			516.8			4.2			(642.3		)		158.5

Total assets at fair value	$	3,477.30		$	1,136.60		$	4.2		$	(2,990.4	)		$	1,627.70

Liabilities:
Accounts payable and other accrued liabilities - contingent liabilities	$	—		$	—		$	9.6		$	—			$	9.6

Payable to customers - derivatives	2,328.20			—			—			(2,328.2		)		—

Common and preferred stock and ADRs	82.9			16.6			—			—				99.5

Exchangeable foreign ordinary equities and ADRs	8.7			—			—			—				8.7

Derivatives	174			473.2			—			(616.5		)		30.7

Commodities leases	—			85.5			—			(44.5		)		41

Financial instruments sold, not yet purchased	265.6			575.3			—			(661.0		)		179.9

Total liabilities at fair value	$	2,593.80		$	575.3		$	9.6		$	(2,989.2	)		$	189.5


-1	Represents cash collateral and the impact of netting across the levels of the fair value hierarchy. Netting among positions classified within the same level is included in that level.
Realized and unrealized gains and losses are included in ‘trading gains, net’ in the condensed consolidated income statements.
Information on Level 3 Financial Assets and Liabilities
The Company’s financial assets at fair value classified in level 3 of the fair value hierarchy as of December 31, 2013 and September 30, 2013 are summarized below:


(in millions)	December 31, 2013			September 30, 2013
Total level 3 assets	$	4.1		$	4.2

Level 3 assets for which the Company bears economic exposure	$	4.1		$	4.2

Total assets	$	2,743.90		$	2,848.00

Total financial assets at fair value	$	1,554.00		$	1,627.70

Total level 3 assets as a percentage of total assets	0.1		%	0.1		%
Level 3 assets for which the Company bears economic exposure as a percentage of total assets	0.1		%	0.1		%
Total level 3 assets as a percentage of total financial assets at fair value	0.3		%	0.3		%
The following tables set forth a summary of changes in the fair value of the Company’s level 3 financial assets and liabilities during the three months ended December 31, 2013 and 2012, including a summary of unrealized gains (losses) during the respective periods on the Company’s level 3 financial assets and liabilities still held as of December 31, 2013.


	Level 3 Financial Assets and Financial Liabilities
	For the Three Months Ended December 31, 2013
(in millions)	Balances at			Realized gains			Unrealized			Purchases/issuances				Settlements				Transfers in		Balances at
	beginning of			(losses) during			gains (losses)											or (out) of		end of period
	period			period			during period											Level 3
Assets:
Common stock and ADRs	$	0.7		$	—		$	—		$	—			$	—			$	—	$	0.7

Corporate and municipal bonds	3.5			—			(0.1		)	—				—				—		3.4

	$	4.2		$	—		$	(0.1	)	$	—			$	—			$	—	$	4.1

Liabilities:
Contingent liabilities	$	9.6		$	—		$	0.2		$	—			$	(0.7	)		$	—	$	9.1



	Level 3 Financial Assets and Financial Liabilities
	For the Three Months Ended December 31, 2012
(in millions)	Balances at			Realized gains			Unrealized			Purchases/issuances				Settlements				Transfers in		Balances at
	beginning of			(losses) during			gains (losses)											or (out) of		end of period
	period			period			during period											Level 3
Assets:
Common stock and ADRs	$	0.9		$	—		$	—		$	—			$	—			$	—	$	0.9

Corporate and municipal bonds	3.6			—			—			—				—				—		3.6

	$	4.5		$	—		$	—		$	—			$	—			$	—	$	4.5

Liabilities:
Contingent liabilities	$	14.8		$	—		$	0.3		$	3.1			$	(0.3	)		$	—	$	17.9

In accordance with the Fair Value Measurements Topic of the ASC, the Company has estimated on a recurring basis each period the fair value of debentures issued by a single asset owning company of Suriwongse Hotel located in Chiang Mai, Thailand. As of December 31, 2013, the Company’s investment in the hotel is $3.4 million, and included within the corporate and municipal bonds classification in the level 3 financial assets and financial liabilities tables. The Company has classified its investment in the hotel within level 3 of the fair value hierarchy because the fair value is determined using significant unobservable inputs, which include projected cash flows. These cash flows are discounted employing present value techniques. The Company estimates the fair value of its investment in these debentures by using a management-developed forecast, which is based on the income approach. The Company continues to monitor the hotel renovation process and evaluate the fair value of the debentures. There has been no significant change in the fair value of the debentures, and no additional loss has been recognized during the three months ended December 31, 2013 and 2012.
The Company is required to make additional future cash payments based on certain financial performance measures of its acquired businesses. The Company is required to remeasure the fair value of the cash earnout arrangements on a recurring basis in accordance with the guidance in the Business Combinations Topic of the ASC. The Company has classified its liabilities for the contingent earnout arrangements within level 3 of the fair value hierarchy because the fair value is determined using significant unobservable inputs, which include projected cash flows. The estimated fair value of the contingent purchase consideration is based upon management-developed forecasts, a level 3 input in the fair value hierarchy. These cash flows are discounted employing present value techniques in arriving at fair value. The discount rate was developed using market participant company data and there have been no significant changes in the discount rate environment. From the dates of acquisition to December 31, 2013, certain acquisitions have had changes in the estimates of undiscounted cash flows, based on actual performances fluctuating from estimates. The fair value of the contingent consideration increased $0.2 million and $0.3 million during the three months ended December 31, 2013 and 2012, respectively, with the corresponding amount classified as ‘other expense’ in the condensed consolidated income statements.
The Company reports transfers in and out of levels 1, 2 and 3, as applicable, using the fair value of the securities as of the beginning of the reporting period in which the transfer occurred. The Company did not have any transfers between level 1 and level 2 fair value measurements for the three months ended December 31, 2013 and 2012.
The Company has also classified equity investments in exchange firms’ common stock not pledged for clearing purposes as available-for-sale. The investments are recorded at fair value, with unrealized gains and losses recorded, net of taxes, as a component of other comprehensive income (“OCI”) until realized. As of December 31, 2013, the cost and fair value of all the equity investments in exchange firms was $3.7 million and $4.7 million, respectively. As of September 30, 2013, the cost and fair value of the equity investments in exchange firms was $3.7 million and $4.4 million, respectively.
In June 2012, the board of LME Holdings Limited (“LME Holdings”), the parent company of The London Metal Exchange (“LME”), entered into a framework agreement regarding the terms of a recommended cash offer for the entire issued and outstanding ordinary share capital of LME Holdings. In July 2012, the shareholders of LME Holdings approved the sale of LME Holdings to the Hong Kong Exchanges & Clearing Limited. In December 2012, the Company received proceeds of $8.6 million from the sale of its shares in the LME. The shares of the LME were previously held by the Company as available-for-sale and the unrealized gain for those shares was reflected in OCI. For the three months ended December 31, 2012, the Company reclassified the unrealized gain remaining in AOCI of approximately $6.3 million, net of income tax expense of $2.0 million, into the current period earnings.
In December 2012, the Company sold its exchange membership seats in the Board of Trade of Kansas City, Missouri, Inc. (“KCBT”), in connection with the acquisition of the KCBT by Chicago Mercantile Exchange (“CME”). The Company was required to hold these exchange membership seats for clearing purposes and, as a result, the associated KCBT shares were being held at cost on the condensed consolidated balance sheet. The Company received proceeds of $1.5 million and recognized a gain of $0.9 million before taxes, during the three months ended December 31, 2012, in connection with the sale of these seats.
The Company recorded unrealized gains of $0.7 million, net of income tax expense of $0.4 million as of December 31, 2013, and unrealized gains of $0.5 million, net of income tax expense of $0.3 million as of September 30, 2013, in OCI related to U.S. government obligations, mortgage-backed securities and the remaining equity investments in exchange firms classified as available-for-sale securities.
The following tables summarize the amortized cost basis, the aggregate fair value and gross unrealized holding gains and losses of the Company’s investment securities classified as available-for-sale as of December 31, 2013 and September 30, 2013:


December 31, 2013
Amounts included in deposits with and receivables from exchange-clearing organizations and financial instruments owned:
	Amortized			Unrealized Holding						Estimated
(in millions)	Cost			Gains			(Losses)			Fair Value
U.S. government obligations	$	562.8		$	0.1		$	—		$	562.9

Mortgage-backed securities	4.9			0.1			—			5

	$	567.7		$	0.2		$	—		$	567.9




September 30, 2013
Amounts included in deposits with and receivables from exchange-clearing organizations:
	Amortized			Unrealized Holding(1)						Estimated
(in millions)	Cost			Gains			(Losses)			Fair Value
U.S. government obligations	$	568.5		$	—		$	—		$	568.5

Mortgage-backed securities	5.2			0.1			—			5.3

	$	573.7		$	0.1		$	—		$	573.8

(1) Unrealized gain/loss on U.S. government obligations as of September 30, 2013, were less than $0.1 million.
As of December 31, 2013 and September 30, 2013, investments in debt securities classified as available-for-sale (“AFS”) mature as follows:


December 31, 2013
	Due in						Estimated
(in millions)	Less than 1 year			1 year or more			Fair Value
U.S. government obligations	$	562.9		$	—		$	562.9

Mortgage-backed securities	—			5			5

	$	562.9		$	5		$	567.9



September 30, 2013
	Due in						Estimated
(in millions)	Less than 1 year			1 year or more			Fair Value
U.S. government obligations	$	568.5		$	—		$	568.5

Mortgage-backed securities	—			5.3			5.3

	$	568.5		$	5.3		$	573.8

Except as discussed previously, there were no other sales of AFS securities during the three months ended December 31, 2013 and 2012, and as a result, no realized gains or losses were recorded for the three months ended December 31, 2013 and 2012.
For the purposes of the maturity schedule, mortgage-backed securities, which are not due at a single maturity date, have been allocated over maturity groupings based on the expected maturity of the underlying collateral. Mortgage-backed securities may mature earlier than their stated contractual maturities because of accelerated principal repayments of the underlying loans.

Financial_Instruments_with_Off

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk (Notes)	3 Months Ended
	Dec. 31, 2013
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk [Abstract]	'
Derivative Instruments and Hedging Activities Disclosure [Text Block]	'
	Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk
	The Company is party to certain financial instruments with off-balance sheet risk in the normal course of its business. The Company has sold financial instruments that it does not currently own and will therefore be obliged to purchase such financial instruments at a future date. The Company has recorded these obligations in the condensed consolidated financial statements as of December 31, 2013 at the fair values of the related financial instruments. The Company will incur losses if the fair value of the underlying financial instruments increases subsequent to December 31, 2013. The total of $211.4 million as of December 31, 2013 includes $34.3 million for derivative contracts, which represents a liability to the Company based on their fair values as of December 31, 2013.
	Derivatives
	The Company utilizes derivative products in its trading capacity as a dealer in order to satisfy client needs and mitigate risk. The Company manages risks from both derivatives and non-derivative cash instruments on a consolidated basis. The risks of derivatives should not be viewed in isolation, but in aggregate with the Company’s other trading activities. The majority of the Company’s derivative positions are included in the consolidated balance sheets in ‘financial instruments owned, at fair value’, ‘deposits and receivables from exchange-clearing organizations’ and ‘financial instruments sold, not yet purchased, at fair value’.
	The Company employs an interest rate risk management strategy that uses derivative financial instruments in the form of interest rate swaps to manage a portion of the aggregate interest rate position. The Company’s objective is to invest the majority of customer segregated deposits in high quality, short-term investments and swap the resulting variable interest earnings into the medium-term interest stream, by using a strip of interest rate swaps that mature every quarter, in order to achieve the two year moving average of the two year swap rate. The risk mitigation of these interest rate swaps is not within the documented hedging designation requirements of the Derivatives and Hedging Topic of the ASC, and as a result they are recorded at fair value, with changes in the marked-to-market valuation of the financial instruments recorded in ‘trading gains, net’ in the consolidated income statements. The Company did not have any interest rate swaps outstanding at December 31, 2013.
	Listed below are the fair values of the Company’s derivative assets and liabilities as of December 31, 2013 and September 30, 2013. Assets represent net unrealized gains and liabilities represent net unrealized losses.


		December 31, 2013						September 30, 2013
	(in millions)	Assets (1)			Liabilities (1)			Assets (1)			Liabilities (1)
	Derivative contracts not accounted for as hedges:
	Exchange-traded commodity derivatives	$	1,430.00		$	1,311.00		$	2,036.60		$	2,046.30

	OTC commodity derivatives	411.9			419.9			481.4			484.9

	Exchange-traded foreign exchange derivatives	75.3			77.9			89.3			104.2

	OTC foreign exchange derivatives	287.7			274.4			132.3			162.3

	Exchange-traded interest rate derivatives	8.6			3.9			4.3			36

	Equity index derivatives	65.1			101.3			135.5			141.7

	Gross fair value of derivative contracts	2,278.60			2,188.40			2,879.40			2,975.40

	Impact of netting and collateral	(2,281.9		)	(2,154.1		)	(2,940.4		)	(2,944.7		)
	Total fair value included in ‘Deposits and receivables from exchange-clearing organizations’	$	(16.8	)				$	(69.8	)
	Total fair value included in ‘Deposits and receivables from broker-dealers, clearing organizations and counterparties’	$	(5.1	)				$	(13.1	)
	Total fair value included in ‘Financial instruments owned, at fair value’	$	18.6					$	21.9

	Fair value included in ‘Financial instruments sold, not yet purchased, at fair value’				$	34.3					$	30.7


	-1	As of December 31, 2013 and September 30, 2013, the Company’s derivative contract volume for open positions were approximately 3.0 million and 4.1 million contracts, respectively.
	The Company’s derivative contracts are principally held in its Commodities and Risk Management Services (“C&RM”) segment. The Company assists its C&RM segment customers in protecting the value of their future production by entering into option or forward agreements with them on an OTC basis. The Company also provides its C&RM segment customers with sophisticated option products, including combinations of buying and selling puts and calls. The Company mitigates its risk by offsetting the customer’s transaction simultaneously with one of the Company’s trading counterparties or with a similar but not identical position on the exchange. The risk mitigation of these offsetting trades is not within the documented hedging designation requirements of the Derivatives and Hedging Topic of the ASC. These derivative contracts are traded along with cash transactions because of the integrated nature of the markets for these products. The Company manages the risks associated with derivatives on an aggregate basis along with the risks associated with its proprietary trading and market-making activities in cash instruments as part of its firm-wide risk management policies. In particular, the risks related to derivative positions may be partially offset by inventory, unrealized gains in inventory or cash collateral paid or received.
	The following table sets forth the Company’s gains (losses) related to derivative financial instruments for the three months ended December 31, 2013 and 2012, in accordance with the Derivatives and Hedging Topic of the ASC. The gains (losses) set forth below are included in ‘trading gains, net’ in the condensed consolidated income statements.


		Three Months Ended December 31,
	(in millions)	2013			2012
	Commodities	$	8.7		$	30.6

	Foreign exchange	2.1			2.6

	Interest rate	—			0.1

	Net gains (losses) from derivative contracts	$	10.8		$	33.3

	Credit Risk
	In the normal course of business, the Company purchases and sells financial instruments, commodities and foreign currencies as either principal or agent on behalf of its customers. If either the customer or counterparty fails to perform, the Company may be required to discharge the obligations of the nonperforming party. In such circumstances, the Company may sustain a loss if the fair value of the financial instrument or foreign currency is different from the contract value of the transaction.
	The majority of the Company’s transactions and, consequently, the concentration of its credit exposure are with commodity exchanges, customers, broker-dealers and other financial institutions. These activities primarily involve collateralized and uncollateralized arrangements and may result in credit exposure in the event that a counterparty fails to meet its contractual obligations. The Company’s exposure to credit risk can be directly impacted by volatile financial markets, which may impair the ability of counterparties to satisfy their contractual obligations. The Company seeks to control its credit risk through a variety of reporting and control procedures, including establishing credit limits based upon a review of the counterparties’ financial condition and credit ratings. The Company monitors collateral levels on a daily basis for compliance with regulatory and internal guidelines and requests changes in collateral levels as appropriate.
	The Company is a party to financial instruments in the normal course of its business through customer and proprietary trading accounts in exchange-traded and OTC derivative instruments. These instruments are primarily the execution of orders for commodity futures, options on futures and forward foreign currency contracts on behalf of its customers, substantially all of which are transacted on a margin basis. Such transactions may expose the Company to significant credit risk in the event margin requirements are not sufficient to fully cover losses which customers may incur. The Company controls the risks associated with these transactions by requiring customers to maintain margin deposits in compliance with individual exchange regulations and internal guidelines. The Company monitors required margin levels daily and, therefore, may require customers to deposit additional collateral or reduce positions when necessary. The Company also establishes credit limits for customers, which are monitored daily. The Company evaluates each customer’s creditworthiness on a case by case basis. Clearing, financing, and settlement activities may require the Company to maintain funds with or pledge securities as collateral with other financial institutions. Generally, these exposures to both customers and exchanges are subject to master netting, or customer agreements, which reduce the exposure to the Company by permitting receivables and payables with such customers to be offset in the event of a customer default. Management believes that the margin deposits held as of December 31, 2013 and September 30, 2013 were adequate to minimize the risk of material loss that could be created by positions held at that time. Additionally, the Company monitors collateral fair value on a daily basis and adjusts collateral levels in the event of excess market exposure. Generally, these exposures to both customers and counterparties are subject to master netting or customer agreements which reduce the exposure to the Company.
	Derivative financial instruments involve varying degrees of off-balance sheet market risk whereby changes in the fair values of underlying financial instruments may result in changes in the fair value of the financial instruments in excess of the amounts reflected in the condensed consolidated balance sheets. Exposure to market risk is influenced by a number of factors, including the relationships between the financial instruments and the Company’s positions, as well as the volatility and liquidity in the markets in which the financial instruments are traded. The principal risk components of financial instruments include, among other things, interest rate volatility, the duration of the underlying instruments and changes in foreign exchange rates. The Company attempts to manage its exposure to market risk through various techniques. Aggregate market limits have been established and market risk measures are routinely monitored against these limits.

Receivables_From_Customers_Net

Receivables From Customers, Net and Notes Receivable, Net (Notes)	3 Months Ended
	Dec. 31, 2013
Receivables from customers and notes receivable, net [Abstract]	'
Financing Receivables [Text Block]	'
	Receivables From Customers, Net and Notes Receivable, Net
	Receivables from customers, net and notes receivable, net include an allowance for bad debts, which reflects the Company’s best estimate of probable losses inherent in the receivables from customers and notes receivable. The Company provides for an allowance for doubtful accounts based on a specific-identification basis. The Company continually reviews its allowance for bad debts. The allowance for doubtful accounts related to receivables from customers was $1.4 million and $1.1 million as of December 31, 2013 and September 30, 2013, respectively. The allowance for doubtful accounts related to notes receivable was $0.1 million as of December 31, 2013 and September 30, 2013.
	During the three months ended December 31, 2013, the Company recorded bad debt expense of $0.4 million, including provision increases of $0.3 million and direct write-offs of $0.1 million. During the three months ended December 31, 2012, the Company recorded bad debt expense of $0.4 million, representing provision increases.
	The Company originates short-term notes receivable from customers with the outstanding balances being insured 90% to 98% by a third party, including accrued interest. The total balance outstanding under insured notes receivable was $17.3 million and $21.1 million as of December 31, 2013 and September 30, 2013, respectively. The Company has sold $16.0 million and $18.7 million of the insured portion of the notes through non-recourse participation agreements with other third parties as of December 31, 2013 and September 30, 2013, respectively.
	See discussion of notes receivable related to commodity repurchase agreements in Note 10.

Physical_Commodities_Inventory

Physical Commodities Inventory (Notes)	3 Months Ended
	Dec. 31, 2013
Physical Commodities Inventory [Abstract]	'
Inventory Disclosure [Text Block]	'
	Physical Commodities Inventory
	Physical commodities inventories are stated at the lower of cost or market (“LCM”) using the weighted-average price and first-in first-out cost method. Cost includes finished commodity or raw material and processing costs related to the purchase and processing of inventories. Commodities in process include commodities in the process of being recycled. The carrying values of the Company’s inventory as of December 31, 2013 and September 30, 2013 are shown below.


	(in millions)	December 31,		September 30, 2013
		2013
	Physical commodities inventory - finished commodities	$	26.6	$	59

	As a result of declining market prices for some commodities, the Company has recorded LCM adjustments for physical commodities inventory of $0.3 million and $0.9 million as of December 31, 2013 and September 30, 2013, respectively. The adjustments are included in ‘cost of sales of physical commodities’ in the condensed consolidated income statements.

Goodwill_Notes

Goodwill (Notes)	3 Months Ended
	Dec. 31, 2013
Goodwill [Abstract]	'
Goodwill Disclosure [Text Block]	'
	Goodwill
	The carrying value of goodwill by segment is as follows:


	(in millions)	December 31,		September 30,
		2013		2013
	Commodity and Risk Management Services	$	33.1	$	33.1

	Foreign Exchange	6.3		6.3

	Securities	8.1		8.1

	Goodwill	$	47.5	$	47.5

Intangible_Assets_Notes

Intangible Assets - (Notes)	3 Months Ended
	Dec. 31, 2013
Intangible Assets [Abstract]	'
Intangible Assets Disclosure [Text Block]	'
	Intangible Assets
	The gross and net carrying values of intangible assets as of the balance sheet dates, by major intangible asset class are as follows:


		December 31, 2013							September 30, 2013
	(in millions)	Gross Amount		Accumulated			Net Amount		Gross Amount		Accumulated			Net Amount
				Amortization							Amortization
	Intangible assets subject to amortization
	Noncompete agreement	$	—	$	—		$	—	$	3.7	$	(3.7	)	$	—

	Trade name	—		—			—		0.7		(0.7		)	—

	Software programs/platforms	2.2		(1.6		)	0.6		2.2		(1.5		)	0.7

	Customer base	12.4		(2.8		)	9.6		12.4		(2.6		)	9.8

		14.6		(4.4		)	10.2		19		(8.5		)	10.5

	Intangible assets not subject to amortization
	Trade name	1.1		—			1.1		1.1		—			1.1

	Total intangible assets	$	15.7	$	(4.4	)	$	11.3	$	20.1	$	(8.5	)	$	11.6

	Amortization expense related to intangible assets was $0.3 million and $0.6 million for the three months ended December 31, 2013 and 2012, respectively.
	As of December 31, 2013, the estimated future amortization expense was as follows:


	(in millions)
	Fiscal 2014 (remaining nine months)	$	1

	Fiscal 2015	1.1

	Fiscal 2016	0.7

	Fiscal 2017	0.7

	Fiscal 2018	0.7

	Fiscal 2019 and thereafter	6

		$	10.2

Credit_Facilities_Notes

Credit Facilities (Notes)

3 Months Ended

Dec. 31, 2013

Credit Facilities [Abstract]

Debt Disclosure [Text Block]

Credit Facilities

Variable-Rate Credit Facilities

The Company has four committed credit facilities under which the Company and its subsidiaries may borrow up to $315.0 million, subject to the terms and conditions for these facilities. The amounts outstanding under these credit facilities are short term borrowings and carry variable rates of interest, thus approximating fair value.

The Company’s credit facilities consist of the following:

•

$140.0 million facility available to INTL FCStone Inc. for general working capital requirements, committed until September 20, 2016. The facility is secured by a pledge of shares held in certain of the Company’s subsidiaries.

•

$75.0 million facility available to the Company’s wholly owned subsidiary, FCStone, LLC, for short-term funding of margin to commodity exchanges, committed until April 10, 2014. The facility is subject to annual review and guaranteed by INTL FCStone Inc.

•

$75.0 million facility available to the Company’s wholly owned subsidiary, FCStone Merchant Services, LLC, for financing traditional commodity financing arrangements and commodity repurchase agreements, committed until May 1, 2014. The facility is subject to annual review, and is secured by the assets of FCStone Merchants and guaranteed by INTL FCStone Inc.

•

$25.0 million facility available to the Company’s wholly owned subsidiary, INTL FCStone Ltd, for short-term funding of margin to commodity exchanges, committed until November 10, 2014. The facility is subject to annual review, and the facility is guaranteed by INTL FCStone Inc.

Senior Unsecured Notes

In July 2013, the Company completed the offering of $45.5 million aggregate principal amount of the Company’s 8.5% Senior Notes due 2020 (the “Notes”). The net proceeds of the sale of the Notes are being used for general corporate purposes. The Notes were issued under an Indenture dated as of July 22, 2013, between the Company and The Bank of New York Mellon, as Trustee. The Notes bear interest at a rate of 8.5% per year (payable quarterly on January 30, April 30, July 30 and October 30 of each year). The Notes mature on July 30, 2020. The Company may redeem the Notes, in whole or in part, at any time on and after July 30, 2016, at a redemption price equal to 100% of the principal amount redeemed plus accrued and unpaid interest to, but not including, the redemption date. The Company incurred debt issuance costs of $1.7 million in connection with the issuance of the Notes, which are being amortized over the term of the Notes.

The following table sets forth a listing of credit facilities, the committed amounts as of December 31, 2013 on the facilities, and outstanding borrowings on the facilities as well as indebtedness on senior notes as of December 31, 2013 and September 30, 2013:

(in millions)

Credit Facilities

Amounts Outstanding

Borrower

Security

Renewal / Expiration Date

Total Commitment

December 31,

September 30,

2013

INTL FCStone Inc.

Certain pledged shares

September 20, 2016

140

FCStone, LLC

None

April 10, 2014

—

FCStone Merchants

Certain commodities assets

May 1, 2014

11.2

INTL FCStone, Ltd.

None

November 10, 2014

—

315

60.2

Senior Unsecured Notes

8.50% senior notes, due July 30, 2020

45.5

Total indebtedness

105.7

106.5

As shown above, $175 million of the Company’s committed credit facilities are scheduled to expire during the next twelve months. The Company intends to renew or replace these facilities as they expire, and based on the Company’s liquidity position and capital structure, the Company believes it will be able to do so.

The Company’s credit facility agreements contain financial covenants relating to financial measures on a consolidated basis, as well as on a certain stand-alone subsidiary basis, including minimum tangible net worth, minimum regulatory capital, minimum net unencumbered liquid assets, maximum net loss, minimum fixed charge coverage ratio and maximum funded debt to net worth ratio. Failure to comply with these covenants could result in the debt becoming payable on demand. As of December 31, 2013, the Company was in compliance with all of its financial covenants under its credit facilities.

The agreement with INTL FCStone Inc. as borrower also includes a non-financial covenant that requires the Company to provide audited financial statements for each fiscal year within ninety days after the end of the fiscal year. The Company was unable to deliver the audited financial statements for the fiscal year ended September 30, 2013 within the required time period. The Company requested and was granted a waiver from the lenders, dated December 23, 2013, extending the time period the Company had to provide the audited financial statements. The Company provided its audited financial statements for the fiscal year ended September 30, 2013 within the extended period.

Commodity_and_Other_Repurchase

Commodity and Other Repurchase Agreements (Notes)	3 Months Ended
Commodity and Other Repurchase Agreements (Notes)	Dec. 31, 2013
Commodity and Other Repurchase Agreements [Abstract]	'
Repurchase Agreements, Resale Agreements, Securities Borrowed, and Securities Loaned Disclosure [Text Block]	'
	Commodity and Other Repurchase Agreements
	The Company’s outstanding notes receivable in connection with sale/repurchase agreements, under which customers sell certain commodity inventory and agree to repurchase the commodity inventory at a future date at either a fixed or floating rate, as of December 31, 2013 and September 30, 2013 were $22.0 million and $9.2 million, respectively.
	The obligations outstanding related to commodities sold under repurchase agreements that are recorded in ‘lenders under loans’ as of December 31, 2013 and September 30, 2013 were $11.2 million and $6.0 million, respectively.

Commitments_and_Contingencies_

Commitments and Contingencies (Notes)	3 Months Ended
Commitments and Contingencies (Notes)	Dec. 31, 2013
Commitments and Contingencies [Abstract]	'
Commitments and Contingencies Disclosure [Text Block]	'
	Commitments and Contingencies
	Legal and Regulatory Proceedings
	Certain conditions may exist as of the date that the financial statements are issued, which may result in a loss to the Company but which will only be resolved when one or more future events occur or fail to occur. The Company assesses such contingent liabilities, and such assessment inherently involves an exercise of judgment. In assessing loss contingencies related to legal and regulatory proceedings that are pending against the Company or unasserted claims that may result in such proceedings, the Company’s legal counsel evaluates the perceived merits of any legal proceedings or unasserted claims as well as the perceived merits of the amount of relief sought or expected to be sought therein.
	If the assessment of a contingency indicates that it is probable that a material loss had been incurred at the date of the financial statements and the amount of the liability can be estimated, then the estimated liability would be accrued in the Company’s financial statements. If the assessment indicates that a potentially material loss contingency is not probable, but is reasonably possible, or is probable but cannot be estimated, then the nature of the contingent liability, together with an estimate of the range of possible loss if determinable and material, would be disclosed. Neither accrual nor disclosure is required for loss contingencies that are deemed remote. The Company accrues legal fees related to contingent liabilities as they are incurred.
	In addition to the matters discussed below, from time to time and in the ordinary course of business, the Company is involved in various legal actions and proceedings, including tort claims, contractual disputes, employment matters, workers’ compensation claims and collections. The Company carries insurance that provides protection against certain types of claims, up to the policy limits of the insurance.
	As of December 31, 2013 and September 30, 2013, the condensed consolidated balance sheets include loss contingency accruals recorded prior to September 30, 2013 which are not material, individually or in the aggregate, to the Company’s financial position or liquidity. In the opinion of management, possible exposure from loss contingencies in excess of the amounts accrued, and in addition to the possible losses discussed below, is not likely to be material to the Company’s earnings, financial position or liquidity.
	The following is a summary of significant legal matters involving the Company.
	Securities Litigation and Regulatory Proceedings
	In August 2008, shareholders filed a derivative action against FCStone and certain directors of FCStone in the Circuit Court of Platte County, Missouri, alleging breaches of fiduciary duties, waste of corporate assets and unjust enrichment. Shareholders subsequently filed an amended complaint in May 2009 to add claims based upon the losses sustained by FCStone arising out of a customer energy trading account. In July 2009, the same plaintiff filed a motion for leave to amend the existing case to add a purported class action claim on behalf of the holders of FCStone common stock.
	In July 2009, plaintiffs filed a purported shareholder class action complaint against FCStone and its directors, as well as the Company in the Circuit Court of Clay County, Missouri. The complaint alleged that FCStone and its directors breached their fiduciary duties by failing to maximize stockholder value in connection with the contemplated acquisition of FCStone by the Company. This complaint was subsequently consolidated with the complaint filed in the Circuit Court of Platte County, Missouri. The plaintiffs subsequently filed an amended consolidated complaint which does not assert any claims against the Company. This complaint purports to be filed derivatively on FCStone’s and the Company’s behalf and against certain of FCStone’s current and former directors and officers and directly against the same individuals. The Company, FCStone, and the defendants filed motions to dismiss on multiple grounds. The parties to the litigation have reached an agreement in principle to settle this matter. This agreement was provisionally approved by the court on December 4, 2013, and is expected to be finally approved on March 19, 2014. The agreement, if finally approved, would result in the Company incurring a legal cost of $265,000 after consideration of expected insurance coverage.
	In November 2011, the Commodity Futures Trading Commission (“CFTC”) Division of Enforcement Staff (“Staff”) requested the Company to voluntarily produce specified documents to the Staff in connection with its then informal investigation of the losses that occurred in 2008 and 2009 in the customer energy trading account of FCStone, LLC. In September 2012, the Staff provided the Company with a Wells notice, indicating the Staff’s intention to recommend that the CFTC bring certain charges against FCStone, LLC. The Company filed its Wells submission with the Staff in October 2012. On May 29, 2013, the Company reached a settlement with the CFTC in this matter. The CFTC’s findings, neither admitted nor denied by the Company, were that FCStone, LLC violated CFTC Regulation 166.3 in that it failed to diligently supervise its officers’ and employees’ activities relating to risks associated with its customers’ accounts, and in particular one account controlled by two of FCStone’s customers who traded in natural gas futures, swaps and option contracts.
	The settlement, with appropriate waivers and consents, required FCStone, LLC to appoint an independent third party reviewer to review and evaluate FCStone LLC’s existing policies and procedures relating to certain risks, to ensure that we have made sufficient modifications to its risk controls since 2008. An independent third party reviewer was appointed, and the review process is progressing, but has not yet been completed.
	Sentinel Litigation
	The Company’s subsidiary, FCStone, LLC, had a portion of its excess segregated funds invested with Sentinel Management Group Inc. (“Sentinel”), a registered FCM and an Illinois-based money manager that provided cash management services to other FCMs. In August 2007, Sentinel halted redemptions to customers and sold certain of the assets it managed to an unaffiliated third party at a significant discount. On August 17, 2007, subsequent to Sentinel’s sale of certain assets, Sentinel filed for bankruptcy protection and $15.5 million of FCStone, LLC’s $21.9 million in invested funds were returned to it.
	In August 2008, the bankruptcy trustee of Sentinel filed adversary proceedings against FCStone, LLC, and a number of other FCMs in the Bankruptcy Court for the Northern District of Illinois. The case was subsequently reassigned to the United States District Court, for the Northern District of Illinois. In the complaint, the trustee is seeking avoidance of alleged transfers or withdrawals of funds received by FCStone, LLC and other FCMs within 90 days prior to the filing of the Sentinel bankruptcy petition, as well as avoidance of post-petition distributions and disallowance of the proof of claim filed by FCStone, LLC. The trustee seeks recovery of pre- and post-petition transfers totaling approximately $15.5 million. In April 2009, the trustee filed an amended complaint adding a claim for unjust enrichment. FCStone, LLC answered the complaints and all parties entered into the discovery phase of the litigation. In January 2011, the trustee filed a motion for summary judgment on various counts in the adversary proceedings filed in August 2008 against FCStone, LLC and a number of other FCMs. In January 2012, FCStone, LLC filed a motion for summary judgment in its favor with respect to the transfer of approximately $1.1 million to its customer segregated account on August 17, 2007, pursuant to the “safe harbor” provisions of Section 546(e) of the U.S. Bankruptcy Code. In April 2012, FCStone, LLC filed a motion to dismiss a portion of the trustee’s claims set forth in its amended complaint. The trial of this matter took place, as a test case, during October 2012. The trial court entered a judgment against FCStone, LLC on January 4, 2013. On January 17, 2013, the trial court entered an agreed order, staying execution and enforcement, pending an appeal of the judgment. By agreement, FCStone, LLC was required to post an appeal cash deposit of $8.0 million with the court, which was deposited on January 18, 2013. The oral arguments in the appeal were heard on December 10, 2013. Based on the merits of the Company’s appeal, management believes a loss is not probable, and thus has not recorded a provision for this matter. The Company believes that if the appeal is unsuccessful, the resulting pre-tax loss to FCStone, LLC would be in the range of $4 million to $6 million.
	Contractual Commitments
	Contingent Liabilities - Acquisitions
	Under the terms of the purchase agreements related to the acquisitions listed below, the Company has obligations to pay additional consideration if specific conditions and earnings targets are met. In accordance with the Business Combinations Topic of the ASC, the fair value of the additional consideration is recognized as a contingent liability as of the acquisition date. The contingent liability for these estimated additional purchase price considerations of $9.1 million and $9.6 million are included in ‘accounts payable and other accrued liabilities’ in the condensed consolidated balance sheets as of December 31, 2013 and September 30, 2013. The acquisition date fair value of additional consideration is remeasured to its fair value each reporting period, with changes in fair value recorded in current earnings. The change in fair value during the three months ended December 31, 2013 and 2012 were increases of $0.2 million and $0.3 million, respectively, and are included in ‘other’ in the consolidated income statements.
	The Company has a contingent liability relating to the December 2012 acquisition of the accounts of Tradewire Securities, LLC, which may result in the payment of additional purchase price consideration. The contingent liability recorded represents the fair value of the expected consideration to be paid, based on the forecasted adjusted pre-tax net earnings during three annual periods and a six month period, after the third annual period, following the closing of the acquisition, for a total of four payments, with a discount rate being applied to those future payments. The change in fair value during the three months ended December 31, 2013 was an increase of $0.2 million, included in ‘other’ in the consolidated income statement. The present value of the estimated total purchase price, including contingent consideration, is $6.6 million as of December 31, 2013, which remains outstanding and is included in ‘accounts payable and other accrued liabilities’ in the consolidated balance sheet.
	The Company has a contingent liability relating to the November 2011 acquisition of Coffee Network, LLC,subsequently reorganized as a division of FCStone, LLC, which may result in the payment of additional purchase price consideration. The contingent liability recorded represents the fair value of the expected consideration to be paid, based on the forecasted adjusted pre-tax net earnings during the three annual periods following the closing of the acquisition plus a final contingent payment. The acquisition date fair value of additional consideration was estimated to be less than $0.1 million. There was no significant change in fair value for the three months ended December 31, 2013 and 2012. The present value of the estimated total purchase price, including contingent consideration, is less than $0.1 million as of December 31, 2013, which has not been paid and is included in ‘accounts payable and other liabilities’ in the condensed consolidated balance sheet.
	The Company has a contingent liability relating to the October 2010 acquisition of Hencorp Becstone Futures, L.C., subsequently reorganized as a division of FCStone, LLC, which may result in the payment of additional purchase price consideration. The contingent liability recorded represents the fair value of the expected consideration to be paid, based on the forecasted adjusted pre-tax net earnings during the fourth fiscal year following the closing of the acquisition plus an additional final estimated contingent payment and a discount rate being applied to the future payments. There was no significant change in fair value for the three months ended December 31, 2013. The change in fair value for the three months ended December 31, 2012 was an increase of $0.1 million, included in ‘other expense’ in the condensed consolidated income statements. The present value of the estimated total purchase price, including contingent consideration, is $7.5 million as of December 31, 2013, of which $2.5 million has not been paid and is included in ‘accounts payable and other liabilities’ in the condensed consolidated balance sheet.
	Exchange Member Guarantees
	The Company is a member of various exchanges that trade and clear futures and option contracts. Associated with its memberships, the Company may be required to pay a proportionate share of the financial obligations of another member who may default on its obligations to the exchanges. While the rules governing different exchange memberships vary, in general the Company’s guarantee obligations would arise only if the exchange had previously exhausted its resources. In addition, any such guarantee obligation would be apportioned among the other non-defaulting members of the exchange. Any potential contingent liability under these membership agreements cannot be estimated. The Company has not recorded any contingent liability in the condensed consolidated financial statements for these agreements and believes that any potential requirement to make payments under these agreements is remote.

Capital_and_Other_Regulatory_R

Capital and Other Regulatory Requirements (Notes)	3 Months Ended
	Dec. 31, 2013
Capital and Other Regulatory Requirements [Abstract]	'
Regulatory Capital Requirements under Banking Regulations [Text Block]	'
	Capital and Other Regulatory Requirements
	The Company’s activities are subject to significant governmental regulation, both in the United States and overseas. The subsidiaries of the Company were in compliance with all of their regulatory requirements as of December 31, 2013, as follows:


	(in millions)			As of December 31, 2013
	Subsidiary	Regulatory Authority	Requirement Type	Actual		Minimum
						Requirement
	FCStone, LLC	CFTC	Net capital	$	106.9	$	63.3

	FCStone, LLC	CFTC	Segregated funds	$	1,606.10	$	1,582.70

	FCStone, LLC	CFTC	Secured funds	$	69	$	52.4

	INTL FCStone Ltd	FCA (United Kingdom)	Net capital	$	59.7	$	25.8

	INTL FCStone Ltd	FCA (United Kingdom)	Segregated funds	$	65.4	$	64.2

	INTL Global Currencies Limited	FCA (United Kingdom)	Net capital	$	20.5	$	0.5

	INTL FCStone Securities Inc.	SEC	Net capital	$	4.8	$	1

	FCC Investments, Inc.	SEC	Net capital	$	0.3	$	0.3

	FCStone Australia	Australian Securities and Investment Commission	Net capital	$	1.7	$	0.9

	FCStone Australia	New Zealand Clearing Ltd	Capital adequacy	$	11.5	$	4.1

	INTL FCStone DTVM Ltda.	Brazilian Central Bank and Securities and Exchange Commission of Brazil	Capital adequacy	$	1	$	0.6

	INTL Capital S.A.	Rosario Futures Exchange (Argentina)	Capital adequacy	$	5.7	$	0.1

	INTL Capital S.A.	General Inspector of Justice (Argentina)	Net capital	$	7.6	$	6.7

	INTL CIBSA Sociedad de Bolsa S.A.	Superintendent of Securities Markets of Buenos Aires (Argentina)	Net capital	$	6.4	$	0.2

	Certain other non-U.S. subsidiaries of the Company are also subject to capital adequacy requirements promulgated by authorities of the countries in which they operate. As of December 31, 2013, these subsidiaries were in compliance with their local capital adequacy requirements.

StockBased_Compensation_Notes

Stock-Based Compensation (Notes)	3 Months Ended
	Dec. 31, 2013
Stock-Based Compensation [Abstract]	'
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	'
	Share-Based Compensation
	Share-based compensation expense is included in ‘compensation and benefits’ in the condensed consolidated income statements and totaled $1.1 million and $1.6 million for the three months ended December 31, 2013 and 2012, respectively.
	Stock Option Plan
	The Company sponsors a stock option plan for its directors, officers, employees and consultants. The 2013 Stock Option Plan, which was approved by the Company’s Board of Directors and shareholders, authorizes the Company to issue stock options covering up to 1.0 million shares of the Company’s common stock. As of December 31, 2013, there were 1.0 million shares available for future grant under this plan. The Company settles stock option exercises with newly issued shares of common stock. There were no options granted during the three months ended December 31, 2013.
	The following is a summary of stock option activity for the three months ended December 31, 2013:


		Shares		Number of		Weighted		Weighted				Weighted	Aggregate
		Available for		Options		Average Price		Average				Average	Intrinsic
		Grant		Outstanding				Grant Date				Remaining	Value
								Fair Value				Term	($ millions)
												(in years)
	Balances as of September 30, 2013	1,000,000		1,779,983		$	24.76	$	11.44			4.87	$	4.8

	Granted	—		—		$	—	$	—

	Exercised			(44,920	)	$	12.05	$	6.22

	Forfeited	—		—		$	—	$	—

	Expired	—		(32,647	)	$	50.64	$	14.27

	Balances as of December 31, 2013	1,000,000		1,702,416		$	24.6	$	11.52			4.81	$	3.3

	Exercisable as of December 31, 2013			761,103		$	23.91	$	9.75			1.73	$	3.3

	The total compensation cost not yet recognized for non-vested awards of $9.5 million as of December 31, 2013 has a weighted-average period of 6.31 years over which the compensation expense is expected to be recognized. Compensation expense is amortized on a straight-line basis over the vesting period. The total intrinsic value of options exercised during the three months ended December 31, 2013 and 2012 was $0.6 million and $0.5 million, respectively.
	Restricted Stock Plan
	The Company sponsors a restricted stock plan for its directors, officers and employees. As of December 31, 2013, 1,138,250 shares were authorized for future grant under the 2012 Restricted Stock Plan. Awards that expire or are canceled generally become available for issuance again under the plan. The Company utilizes newly issued shares of common stock to make restricted stock grants.
	The following is a summary of restricted stock activity for the three months ended December 31, 2013:


		Shares		Number of		Weighted		Weighted		Aggregate
		Available for		Shares		Average		Average		Intrinsic
		Grant		Outstanding		Grant Date		Remaining		Value
						Fair Value		Term		($ millions)
								(in years)
	Balances as of September 30, 2013	1,154,862		363,638		$	20.53	1.74		$	7.4

	Granted	(47,423	)	47,423		$	20.35

	Vested			(102,581	)	$	19.76

	Forfeited	30,811		(54,447	)	$	21.68

	Balances as of December 31, 2013	1,138,250		254,033		$	20.55	2.01		$	4.7

	The total compensation cost not yet recognized of $4.1 million as of December 31, 2013 has a weighted-average period of 2.04 years over which the compensation expense is expected to be recognized. Compensation expense is amortized on a straight-line basis over the vesting period. Restricted stock grants are included in the Company’s total issued and outstanding common shares.

Other_Expenses_Notes

Other Expenses (Notes)	3 Months Ended
	Dec. 31, 2013
Other Expenses [Abstract]	'
Other Expenses [Text Block]	'
	Other Expenses
	Other expenses for the three months ended December 31, 2013 and 2012 consisted of the following:


		Three Months Ended December 31,
	(in millions)	2013		2012
	Contingent consideration, net(1)	$	0.2	$	0.7

	Insurance	0.5		0.5

	Advertising, meetings and conferences	0.4		0.4

	Non-trading hardware and software maintenance and software licensing	0.7		0.6

	Office supplies and printing	0.3		0.3

	Other clearing related expenses	0.4		0.4

	Other non-income taxes	1		1.1

	Other	1.2		2.6

	Total other expenses	$	4.7	$	6.6


	-1	Contingent consideration includes remeasurement of contingent liabilities related to business combinations accounted for in accordance with the provisions of the Business Combinations Topic of the ASC (see Note 3).

Income_Taxes_Notes

Income Taxes (Notes)	3 Months Ended
Income Taxes (Notes)	Dec. 31, 2013
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 our deferred tax assets will not be realized.
	The valuation allowance for deferred tax assets as of December 31, 2013 and September 30, 2013 was $2.3 million. The net change in the total valuation allowance for the year ended September 30, 2013 was a decrease of $1.8 million. The valuation allowances as of December 31, 2013 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 continuing 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. 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 taxes 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 19 years. Based on the tax planning strategies that can be implemented, 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 operations of $1.5 million and $5.5 million for the three months ended December 31, 2013 and 2012, respectively, reflect estimated federal, foreign and state taxes.
	For the three months ended December 31, 2013, the Company’s effective tax rate was 38% compared to 29% for the three months ended December 31, 2012.
	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. 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.

Acquisitions_and_Dispositions_

Acquisitions and Dispositions (Notes)	3 Months Ended
Acquisitions and Dispositions (Notes)	Dec. 31, 2013
Acquisitions [Abstract]	'
Business Combination Disclosure [Text Block]	'
	Acquisitions and Disposals
	First American Capital and Trading Corp.
	On November 18, 2013, First American Capital and Trading Corp. (“FACT”) transfered its customer accounts to INTL FCStone Inc.’s broker-dealer subsidiary, INTL FCStone Securities Inc. FACT provided correspondent clearing services to institutional customers directly and through a global network of partners. FACT serviced a wide range of customers, including broker-dealers, investment advisors, and fund managers.
	The consideration to be paid for the acquisition of institutional accounts from FACT consists of contingent payments based on the pre-tax earnings of the institutional account division created following this transfer. The purchase price for the acquisition is not material to the condensed consolidated financial statements.
	Exit of Physical Base Metals Business
	During the second quarter of fiscal 2013, as a result of a change in management strategy in the Company’s base metals product line, the Company elected to pursue an exit of its physical base metals business through the sale and orderly liquidation of current open positions. During the following months, the Company completed a sale of a portion of the physical base metals open contract positions, and the liquidation of the majority of the remaining physical base metals open contract positions and inventory. The exit of the physical base metals business was substantially completed by the end of fiscal 2013, including the termination of the physical base metals trading team and certain operational support personnel. The remaining open contract positions will be fulfilled during the second fiscal quarter of 2014. The Company expects to present the physical base metals activities in the financial statements as discontinued operations beginning in the second quarter of fiscal 2014. The performance of the physical base metals activities resulted in pre-tax income of $0.1 million and $4.7 million during the three month period ended December 31, 2013 and 2012, respectively. The physical base metals business is included in the C&RM Segment. The Company continues to operate the portion of its base metals business related to non-physical assets, conducted primarily through the London Metals Exchange.
	The Company has considered the impact of the exit of the physical base metals business on the Company’s financial position, future operating results and liquidity, and believes the exit will not have a material negative impact to the condensed consolidated financial statements, expected cash flows or liquidity of the Company. The Company evaluated the recoverability of long-lived and intangible assets as a result of this planned exit, noting no impairment charges. The Company believes any additional exit costs will not be material to the condensed consolidated financial statements.

Segment_Analysis_Notes

Segment Analysis (Notes)	3 Months Ended
	Dec. 31, 2013
Segment Analysis [Abstract]	'
Segment Reporting Disclosure [Text Block]	'
	Segment Analysis
	The Company reports its operating segments based on services provided to customers. The Company’s activities are divided into the following functional areas:

	•	Commodity and Risk Management Services

	•	Foreign Exchange

	•	Securities

	•	Clearing and Execution Services

	•	Other
	Commodity and Risk Management Services (C&RM)
	The Company serves its commercial customers through its force of risk management consultants with a high value added service that differentiates the Company from other competitors and maximizes the opportunity to retain customers. The Integrated Risk Management Program (“IRMP®”) involves providing customers with commodity risk management consulting services that are designed to develop a customized long term hedging program to help them mitigate their exposure to commodity price risk and maximize the amount and certainty of their operating profits. Customers are assisted in the execution of their hedging strategies through the Company’s exchange-traded futures and options clearing and execution operations and through access to more customized alternatives provided by the OTC trading desk. Generally, customers direct their own trading activity and risk management consultants do not have discretionary authority to transact trades on behalf of customers. When transacting OTC contracts with customers, the Company may offset the customer’s transaction simultaneously with one of its trading counterparties. Alternatively, the OTC trade desk will accept a customer transaction and offset that transaction with a similar but not identical position on the exchange.
	In addition, the Company provides a full range of trading and hedging capabilities to select producers, consumers, recyclers and investors in both precious and base metals, as well as certain other related commodities. For base metals, following the exit of the physical trading business, this will involve acting as a Category One ring dealing member of the LME, providing execution, clearing and advisory services in exchange traded futures and OTC products. In precious metals, in addition to offering OTC products, the Company acts as a principal, committing its own capital to buy and sell precious metals on a spot and forward basis.
	The Company records its physical commodities revenues on a gross basis. Operating revenues and losses from the Company’s commodities derivatives activities are included in ‘trading gains, net’ in the condensed consolidated income statements. Inventory for the commodities business is valued at the lower of cost or fair value, under the provisions of the Inventory Topic of the ASC. The Company generally mitigates the price risk associated with commodities held in inventory through the use of derivatives. The Company does not elect hedge accounting under U.S. GAAP in accounting for this price risk mitigation. In such situations, unrealized gains in inventory are not recognized under U.S. GAAP, but unrealized gains and losses in related derivative positions are recognized under U.S. GAAP. As a result, the Company’s reported earnings from commodities trading may be subject to significant volatility when calculated under U.S. GAAP.
	Foreign Exchange
	The Company provides treasury, global payment and foreign exchange services to financial institutions, multi-national corporations, government organizations and charitable organizations as well as assisting commercial customers with the execution of foreign exchange hedging strategies. The Company transacts in over 130 currencies and specializes in smaller, more difficult emerging markets where there is limited liquidity. In addition, the Company executes trades based on the foreign currency flows inherent in the Company’s existing business activities. The Company primarily acts as a principal in buying and selling foreign currencies on a spot basis. The Company derives revenue from the difference between the purchase and sale prices.
	The Company also provides spot foreign currency trading for a customer base of eligible contract participants and high net worth retail customers as well as operating a proprietary foreign exchange desk which arbitrages the futures and cash markets.
	Securities
	Through INTL FCStone Securities, Inc., the Company acts as a wholesale market maker in select foreign securities including unlisted ADRs and foreign ordinary shares and provides execution in select debt instruments and exchange-traded funds (“ETFs”). The Company provides execution and liquidity to national broker-dealers, regional broker-dealers and institutional investors. The Company also provides global execution services for institutional customers, including hedge funds, pension funds, broker-dealers and banks located primarily in Latin America, the Caribbean, North America and Europe.
	The Company makes markets in approximately 800 ADRs and foreign ordinary shares traded in the OTC market. In addition, the Company will, on request, make prices in more than 8,000 other ADRs and foreign common shares. As a market-maker, the Company provides trade execution services by offering to buy shares from, or sell shares to, broker-dealers and institutions. The Company displays the prices at which it is willing to buy and sell these securities and adjusts its prices in response to market conditions. When acting as principal, the Company commits its own capital and derives revenue from the difference between the prices at which the Company buys and sells shares. The Company also earns commissions by executing trades on an agency basis.
	While the Company’s customers are other broker-dealers and institutions, the business tends to be driven by the needs of the private clients of those broker-dealers and institutions. The size of private client trades may be uneconomical for the in-house international equities trading desks of our customers to execute. The Company is able to provide execution of smaller trades at profitable margins.
	The Company provides a full range of investment banking advisory services to commercial customers including the issuance of loans or equity. The Company also originates, structures and places a wide array of emerging market debt instruments in the international and domestic capital markets. These instruments include complex asset backed securities, unsecured bond and loan issues, negotiable notes and other trade-related debt instruments used in cross-border trade finance. On occasions the Company may invest its own capital in debt instruments before selling them. It also actively trades in a variety of international debt instruments.
	Clearing and Execution Services (CES)
	The Company seeks to provide competitive and efficient clearing and execution of exchange-traded futures and options-on-futures for the institutional and professional trader market segments. Through its platform, customer orders are accepted and directed to the appropriate exchange for execution. The Company then facilitates the clearing of customers’ transactions. Clearing involves the matching of customers’ trades with the exchange, the collection and management of margin deposits to support the transactions, and the accounting and reporting of the transactions to customers. The Company seeks to leverage its capabilities and capacity by offering facilities management or outsourcing solutions to other FCMs.
	Other
	This segment consists of the Company’s asset management and commodity financing and facilitation business. The asset management revenues include fees, commissions and other revenues received by the Company for management of third party assets and investment gains or losses on the Company’s investments in funds and proprietary accounts managed either by the Company’s investment managers or by independent investment managers.
	The Company operates a commodity financing and facilitation business which provides financing to commercial commodity-related companies against physical inventories, including grain, lumber, meats, energy products and renewable fuels. Sale and repurchase agreements are used to purchase commodities evidenced by warehouse receipts, subject to a simultaneous agreement to sell such commodities back to the original seller at a later date. These transactions are accounted for as product financing arrangements, and accordingly no commodity inventory, purchases or sales are recorded. Additionally, the Company, as a principal, engages in physical purchase and sale transactions related to inputs to the renewable fuels and feed ingredient industries.
	********
	The total revenues reported combine gross revenues for the physical commodities business and net revenues for all other businesses. In order to reflect the way that the Company’s management views the results, the tables below also reflect the segment contribution to ‘operating revenues’, which is shown on the face of the condensed consolidated income statements and which is calculated by deducting physical commodities cost of sales from total revenues.
	Segment data includes the profitability measure of net contribution by segment. Net contribution is one of the key measures used by management to assess the performance of each segment and for decisions regarding the allocation of the Company’s resources. Net contribution is calculated as revenue less direct cost of sales, transaction-based clearing expenses, variable compensation, introducing broker commissions, and interest expense. Variable compensation paid to risk management consultants/traders generally represents a fixed percentage of an amount equal to revenues generated, and in some cases, revenues produced less transaction-based clearing charges, base salaries and an overhead allocation.
	Segment data also includes segment income which is calculated as net contribution less non-variable direct expenses of the segment. These non-variable direct expenses include trader base compensation and benefits, operational employee compensation and benefits, communication and data services, business development, professional fees, bad debt expense and other direct expenses.
	Inter-segment revenues, charges, receivables and payables are eliminated upon consolidation, except revenues and costs related to foreign currency transactions undertaken on an arm’s length basis by the foreign exchange trading business for the securities business. The foreign exchange trading business competes for this business as it does for any other business. If its rates are not competitive, the securities businesses buy or sell their foreign currency through other market counterparties.
	On a recurring basis, the Company sweeps excess cash from certain operating segments to a centralized corporate treasury function in exchange for an intercompany receivable asset. The intercompany receivable asset is eliminated during consolidation, and therefore this practice may impact reported total assets between segments.
	Information concerning operations in these segments of business is shown in accordance with the Segment Reporting Topic of the ASC as follows:


		Three Months Ended December 31,
	(in millions)	2013				2012
	Total revenues:
	Commodity and Risk Management Services	$	7,766.90			$	12,453.10

	Foreign Exchange	18.3				16.2

	Securities	17.6				12.9

	Clearing and Execution Services	23.8				22.4

	Other	111.8				39.5

	Corporate unallocated	(0.4		)		8.7

	Total	$	7,938.00			$	12,552.80

	Operating revenues (loss):
	Commodity and Risk Management Services	$	48.5			$	60.7

	Foreign Exchange	18.3				16.2

	Securities	17.6				12.9

	Clearing and Execution Services	23.8				22.4

Other	5.6				4.8

Corporate unallocated	(0.4		)		8.7

Total	$	113.4			$	125.7

Net contribution:
(Revenues less cost of sales, transaction-based clearing expenses, variable bonus compensation, introducing broker commissions and interest expense)
Commodity and Risk Management Services	$	29.2			$	40.5

Foreign Exchange	12.1				10.4

Securities	8.6				6.9

Clearing and Execution Services	3.7				3.6

Other	4.1				2.8

Total	$	57.7			$	64.2

Segment income (loss):
(Net contribution less non-variable direct segment costs)
Commodity and Risk Management Services	$	13.1			$	22.7

Foreign Exchange	8.1				7.1

Securities	4.3				3.2

Clearing and Execution Services	1.1				(0.9		)

Other	2.9				1.9

Total	$	29.5			$	34

Reconciliation of segment income to income from operations, before tax:
Segment income	$	29.5			$	34

Costs not allocated to operating segments	25.5				15.2

Income from operations, before tax	$	4			$	18.8


(in millions)	As of December 31, 2013				As of September 30, 2013
Total assets:
Commodity and Risk Management Services	$	1,057.20			$	1,105.10

Foreign Exchange	126.8				145

Securities	226.6				198.5

Clearing and Execution Services	1,164.80				1,246.40

Other	54.7				37.3

Corporate unallocated	113.8				115.7

Total	$	2,743.90			$	2,848.00

Subsequent_Event_Notes

Subsequent Event (Notes)	3 Months Ended
Subsequent Event (Notes)	Dec. 31, 2013
Subsequent Events [Abstract]	'
Subsequent Events [Text Block]	'
	Subsequent Events
	On January 13, 2014, a purported class action was filed in the United States District Court for the Southern District of New York against the Company and certain of its officers and directors. The complaint alleges violations of federal securities laws, and claims that the Company has issued false and misleading information concerning the Company’s business and prospects. The action seeks unspecified damages on behalf of persons who purchased the Company’s shares between February 17, 2010 and December 16, 2013. The Company believes the case is without merit and intends to vigorously defend itself.

Basis_of_Presentation_and_Cons1

Basis of Presentation and Consolidation and Recently Issued Accounting Standards (Policies)	3 Months Ended
	Dec. 31, 2013
Basis of Presentation and Consolidation [Abstract]	'
Basis of Accounting, Policy [Policy Text Block]	'
	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.
Consolidation, Policy [Policy Text Block]	'
Consolidation, Policy [Policy Text Block]	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.
Fiscal Period, Policy [Policy Text Block]	'
Fiscal Period, Policy [Policy Text Block]	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.
Use of Estimates, Policy [Policy Text Block]	'
Use of Estimates, Policy [Policy Text Block]	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.
Accounting Changes and Error Corrections [Text Block]	'
	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 [Text Block]	'
	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.
New Accounting Pronouncements, Policy [Policy Text Block]	'
	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.

Earnings_per_Share_Policies

Earnings per Share (Policies)	3 Months Ended
Earnings per Share (Policies)	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share, Potentially Dilutive Securities	'
Earnings Per Share, Potentially Dilutive Securities	The dilutive effect of share-based awards is reflected in diluted net income per share by application of the treasury stock method, which includes consideration of unamortized share-based compensation expense required under the Compensation – Stock Compensation Topic of the Accounting Standards Codification (“ASC”).

Receivables_From_Customers_Net1

Receivables From Customers, Net and Notes Receivable, Net (Policies)	3 Months Ended
	Dec. 31, 2013
Receivables from customers and notes receivable, net [Abstract]	'
Allowance for Receivables from Customers and Notes Receivables [Policy Text Block]	'
	Receivables from customers, net and notes receivable, net include an allowance for bad debts, which reflects the Company’s best estimate of probable losses inherent in the receivables from customers and notes receivable. The Company provides for an allowance for doubtful accounts based on a specific-identification basis. The Company continually reviews its allowance for bad debts.

Commitments_and_Contingencies_1

Commitments and Contingencies (Policies)	3 Months Ended
Commitments and Contingencies (Policies)	Dec. 31, 2013
Commitments and Contingencies [Abstract]	'
Commitments and Contingencies, Policy [Policy Text Block]	'
	Certain conditions may exist as of the date that the financial statements are issued, which may result in a loss to the Company but which will only be resolved when one or more future events occur or fail to occur. The Company assesses such contingent liabilities, and such assessment inherently involves an exercise of judgment. In assessing loss contingencies related to legal and regulatory proceedings that are pending against the Company or unasserted claims that may result in such proceedings, the Company’s legal counsel evaluates the perceived merits of any legal proceedings or unasserted claims as well as the perceived merits of the amount of relief sought or expected to be sought therein.
	If the assessment of a contingency indicates that it is probable that a material loss had been incurred at the date of the financial statements and the amount of the liability can be estimated, then the estimated liability would be accrued in the Company’s financial statements. If the assessment indicates that a potentially material loss contingency is not probable, but is reasonably possible, or is probable but cannot be estimated, then the nature of the contingent liability, together with an estimate of the range of possible loss if determinable and material, would be disclosed. Neither accrual nor disclosure is required for loss contingencies that are deemed remote. The Company accrues legal fees related to contingent liabilities as they are incurred.

Income_Taxes_Policies

Income Taxes (Policies)	3 Months Ended
Income Taxes (Policies)	Dec. 31, 2013
Income Taxes [Abstract]	'
Income Tax, Policy [Policy Text Block]	'
	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 our deferred tax assets will not be realized.

Earnings_per_Share_Tables

Earnings per Share (Tables)	3 Months Ended
	Dec. 31, 2013
Note 2 b Earnings per Share [Abstract]	'
Schedule of Calculation of Numerator and Denominator in Earnings Per Share [Table Text Block]	'
	Basic EPS has been computed by dividing net income by the weighted-average number of common shares outstanding. The following is a reconciliation of the numerator and denominator of the diluted net income per share computations for the periods presented below.


		Three Months Ended December 31,
	(in millions, except share amounts)	2013			2012
	Numerator:
	Net income	$	2.5		$	13.3

	Less: Allocation to participating securities	(0.1		)	(0.5		)
	Income from operations allocated to common stockholders	$	2.4		$	12.8

	Diluted net income	$	2.5		$	13.3

	Less: Allocation to participating securities	(0.1		)	(0.5		)
	Diluted net income allocated to common stockholders	$	2.4		$	12.8

	Denominator:
	Weighted average number of:
	Common shares outstanding	18,657,678			18,266,338

	Dilutive potential common shares outstanding:
	Share-based awards	700,764			512,337

	Diluted weighted-average shares	19,358,442			18,778,675

Assets_and_Liabilities_at_Fair1

Assets and Liabilities, at Fair Value (Tables)	3 Months Ended
	Dec. 31, 2013
Assets and Liabilities, at Fair Value [Abstract]	'
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	'
	The following tables set forth the Company’s financial and nonfinancial assets and liabilities accounted for at fair value, on a recurring basis, as of December 31, 2013 and September 30, 2013 by level in the fair value hierarchy. There were no assets or liabilities that were measured at fair value on a nonrecurring basis as of December 31, 2013 and September 30, 2013.


		December 31, 2013
	(in millions)	Level 1				Level 2				Level 3				Netting and				Total
														Collateral
														-1
	Assets:
	Money market funds	$	0.1			$	—			$	—			$	—			$	0.1

	Certificate of deposits	3				—				—				—				3

	Unrestricted cash equivalents	3.1				—				—				—				3.1

	Commodities warehouse receipts	14.5				—				—				—				14.5

	U.S. government obligations	—				19				—				—				19

	Securities and other assets segregated under federal and other regulations	14.5				19				—				—				33.5

	Money market funds	776.8				—				—				—				776.8

	U.S. government obligations	—				590				—				—				590

	Mortgage-backed securities	—				3.5				—				—				3.5

	Derivatives	1,577.20				—				—				(1,594.0		)		(16.8		)

	Deposits and receivables from exchange-clearing organizations	2,354.00				593.5				—				(1,594.0		)		1,353.50

	Deposits and receivables from broker-dealers, clearing organizations and counterparties - derivatives	0.3				0.9				—				(6.3		)		(5.1		)

	Common and preferred stock and American Depositary Receipts (“ADRs”)	62.3				15.8				0.7				—				78.8

	Exchangeable foreign ordinary equities and ADRs	28.8				—				—				—				28.8

	Corporate and municipal bonds	17.2				—				3.4				—				20.6

	U.S. government obligations	—				0.3				—				—				0.3

	Foreign government obligations	9.8				—				—				—				9.8

	Derivatives	146.4				553.8				—				(681.6		)		18.6

	Commodities leases	—				40.4				—				(39.7		)		0.7

	Exchange firm common stock	4.7				—				—				—				4.7

	Mutual funds and other	5.2				—				—				—				5.2

	Mortgage-backed securities	—				1.5				—				—				1.5

	Financial instruments owned	274.4				611.8				4.1				(721.3		)		169

	Total assets at fair value	$	2,646.30			$	1,225.20			$	4.1			$	(2,321.6	)		$	1,554.00

	Liabilities:
	Accounts payable and other accrued liabilities - contingent liabilities	$	—			$	—			$	9.1			$	—			$	9.1

	Payable to customers - derivatives	1,494.10				—				—				(1,494.1		)		—

	Common and preferred stock and ADRs	91.5				11.3				—				—				102.8

Exchangeable foreign ordinary equities and ADRs	15				—				—				—				15

Corporate and municipal bonds	15.7				0.2				—				—				15.9

Derivatives	151.9				542.4				—				(660.0		)		34.3

Commodities leases	—				82.2				—				(38.8		)		43.4

Financial instruments sold, not yet purchased	274.1				636.1				—				(698.8		)		211.4

Total liabilities at fair value	$	1,768.20			$	636.1			$	9.1			$	(2,192.9	)		$	220.5



-1	Represents cash collateral and the impact of netting across the levels of the fair value hierarchy. Netting among positions classified within the same level is included in that level.


	September 30, 2013
(in millions)	Level 1				Level 2				Level 3				Netting and				Total
													Collateral
													-1
Assets:
Money market funds	$	0.1			$	—			$	—			$	—			$	0.1

Certificate of deposits	2.9				—				—				—				2.9

Unrestricted cash equivalents	3				—				—				—				3

Money market funds	75				—				—				—				75

Commodities warehouse receipts	13.1				—				—				—				13.1

U.S. government obligations	—				19.5				—				—				19.5

Securities and other assets segregated under federal and other regulations	88.1				19.5				—				—				107.6

Money market funds	841.4				—				—				—				841.4

U.S. government obligations	—				594.8				—				—				594.8

Mortgage-backed securities	—				5.3				—				—				5.3

Derivatives	2,263.20				—				—				(2,333.0		)		(69.8		)

Deposits and receivables from exchange-clearing organizations	3,104.60				600.1				—				(2,333.0		)		1,371.70

Deposits and receivables from broker-dealers, clearing organizations and counterparties - derivatives	1.8				0.2				—				(15.1		)		(13.1		)

Common and preferred stock and American Depositary Receipts (“ADRs”)	49.3				19.8				0.7				—				69.8

Exchangeable foreign ordinary equities and ADRs	36.7				—				—				—				36.7

Corporate and municipal bonds	0.1				—				3.5				—				3.6

U.S. government obligations	—				0.3				—				—				0.3

Foreign government obligations	7.7				—				—				—				7.7

Derivatives	173.6				440.6				—				(592.3		)		21.9

Commodities leases	—				56.1				—				(50.0		)		6.1

Commodities warehouse receipts	4				—				—				—				4

Exchange firm common stock	4.4				—				—				—				4.4

Mutual funds and other	4				—				—				—				4

Financial instruments owned	279.8				516.8				4.2				(642.3		)		158.5

Total assets at fair value	$	3,477.30			$	1,136.60			$	4.2			$	(2,990.4	)		$	1,627.70

Liabilities:
Accounts payable and other accrued liabilities - contingent liabilities	$	—			$	—			$	9.6			$	—			$	9.6

Payable to customers - derivatives	2,328.20				—				—				(2,328.2		)		—

Common and preferred stock and ADRs	82.9				16.6				—				—				99.5

Exchangeable foreign ordinary equities and ADRs	8.7				—				—				—				8.7

Derivatives	174				473.2				—				(616.5		)		30.7

Commodities leases	—				85.5				—				(44.5		)		41

Financial instruments sold, not yet purchased	265.6				575.3				—				(661.0		)		179.9

Total liabilities at fair value	$	2,593.80			$	575.3			$	9.6			$	(2,989.2	)		$	189.5


-1	Represents cash collateral and the impact of netting across the levels of the fair value hierarchy. Netting among positions classified within the same level is included in that level.
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	'
	Information on Level 3 Financial Assets and Liabilities
	The Company’s financial assets at fair value classified in level 3 of the fair value hierarchy as of December 31, 2013 and September 30, 2013 are summarized below:


	(in millions)	December 31, 2013				September 30, 2013
	Total level 3 assets	$	4.1			$	4.2

	Level 3 assets for which the Company bears economic exposure	$	4.1			$	4.2

	Total assets	$	2,743.90			$	2,848.00

	Total financial assets at fair value	$	1,554.00			$	1,627.70

	Total level 3 assets as a percentage of total assets	0.1		%		0.1		%
	Level 3 assets for which the Company bears economic exposure as a percentage of total assets	0.1		%		0.1		%
	Total level 3 assets as a percentage of total financial assets at fair value	0.3		%		0.3		%
	The following tables set forth a summary of changes in the fair value of the Company’s level 3 financial assets and liabilities during the three months ended December 31, 2013 and 2012, including a summary of unrealized gains (losses) during the respective periods on the Company’s level 3 financial assets and liabilities still held as of December 31, 2013.


		Level 3 Financial Assets and Financial Liabilities
		For the Three Months Ended December 31, 2013
	(in millions)	Balances at				Realized gains				Unrealized				Purchases/issuances				Settlements			Transfers in		Balances at
		beginning of				(losses) during				gains (losses)											or (out) of		end of period
		period				period				during period											Level 3
	Assets:
	Common stock and ADRs	$	0.7			$	—			$	—			$	—			$	—		$	—	$	0.7

	Corporate and municipal bonds	3.5				—				(0.1		)		—				—			—		3.4

		$	4.2			$	—			$	(0.1	)		$	—			$	—		$	—	$	4.1

	Liabilities:
	Contingent liabilities	$	9.6			$	—			$	0.2			$	—			$	(0.7	)	$	—	$	9.1



		Level 3 Financial Assets and Financial Liabilities
		For the Three Months Ended December 31, 2012
	(in millions)	Balances at				Realized gains				Unrealized				Purchases/issuances				Settlements			Transfers in		Balances at
		beginning of				(losses) during				gains (losses)											or (out) of		end of period
		period				period				during period											Level 3
	Assets:
	Common stock and ADRs	$	0.9			$	—			$	—			$	—			$	—		$	—	$	0.9

	Corporate and municipal bonds	3.6				—				—				—				—			—		3.6

		$	4.5			$	—			$	—			$	—			$	—		$	—	$	4.5

	Liabilities:
	Contingent liabilities	$	14.8			$	—			$	0.3			$	3.1			$	(0.3	)	$	—	$	17.9

Available-for-sale Securities [Table Text Block]	'
	The following tables summarize the amortized cost basis, the aggregate fair value and gross unrealized holding gains and losses of the Company’s investment securities classified as available-for-sale as of December 31, 2013 and September 30, 2013:


	December 31, 2013
	Amounts included in deposits with and receivables from exchange-clearing organizations and financial instruments owned:
		Amortized				Unrealized Holding								Estimated
	(in millions)	Cost				Gains				(Losses)				Fair Value
	U.S. government obligations	$	562.8			$	0.1			$	—			$	562.9

	Mortgage-backed securities	4.9				0.1				—				5

		$	567.7			$	0.2			$	—			$	567.9




	September 30, 2013
	Amounts included in deposits with and receivables from exchange-clearing organizations:
		Amortized				Unrealized Holding(1)								Estimated
	(in millions)	Cost				Gains				(Losses)				Fair Value
	U.S. government obligations	$	568.5			$	—			$	—			$	568.5

	Mortgage-backed securities	5.2				0.1				—				5.3

		$	573.7			$	0.1			$	—			$	573.8

	(1) Unrealized gain/loss on U.S. government obligations as of September 30, 2013, were less than $0.1 million.
	As of December 31, 2013 and September 30, 2013, investments in debt securities classified as available-for-sale (“AFS”) mature as follows:


	December 31, 2013
		Due in								Estimated
	(in millions)	Less than 1 year				1 year or more				Fair Value
	U.S. government obligations	$	562.9			$	—			$	562.9

	Mortgage-backed securities	—				5				5

		$	562.9			$	5			$	567.9



	September 30, 2013
		Due in								Estimated
	(in millions)	Less than 1 year				1 year or more				Fair Value
	U.S. government obligations	$	568.5			$	—			$	568.5

	Mortgage-backed securities	—				5.3				5.3

		$	568.5			$	5.3			$	573.8

	Except as discussed previously, there were no other sales of AFS securities during the three months ended December 31, 2013 and 2012, and as a result, no realized gains or losses were recorded for the three months ended December 31, 2013 and 2012.
	For the purposes of the maturity schedule, mortgage-backed securities, which are not due at a single maturity date, have been allocated over maturity groupings based on the expected maturity of the underlying collateral. Mortgage-backed securities may mature earlier than their stated contractual maturities because of accelerated principal repayments of the underlying loans.

Financial_Instruments_with_Off1

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk (Tables)	3 Months Ended
	Dec. 31, 2013
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk [Abstract]	'
Schedule of Derivative Instruments [Table Text Block]	'
	Listed below are the fair values of the Company’s derivative assets and liabilities as of December 31, 2013 and September 30, 2013. Assets represent net unrealized gains and liabilities represent net unrealized losses.


		December 31, 2013						September 30, 2013
	(in millions)	Assets (1)			Liabilities (1)			Assets (1)			Liabilities (1)
	Derivative contracts not accounted for as hedges:
	Exchange-traded commodity derivatives	$	1,430.00		$	1,311.00		$	2,036.60		$	2,046.30

	OTC commodity derivatives	411.9			419.9			481.4			484.9

	Exchange-traded foreign exchange derivatives	75.3			77.9			89.3			104.2

	OTC foreign exchange derivatives	287.7			274.4			132.3			162.3

	Exchange-traded interest rate derivatives	8.6			3.9			4.3			36

	Equity index derivatives	65.1			101.3			135.5			141.7

	Gross fair value of derivative contracts	2,278.60			2,188.40			2,879.40			2,975.40

	Impact of netting and collateral	(2,281.9		)	(2,154.1		)	(2,940.4		)	(2,944.7		)
	Total fair value included in ‘Deposits and receivables from exchange-clearing organizations’	$	(16.8	)				$	(69.8	)
	Total fair value included in ‘Deposits and receivables from broker-dealers, clearing organizations and counterparties’	$	(5.1	)				$	(13.1	)
	Total fair value included in ‘Financial instruments owned, at fair value’	$	18.6					$	21.9

	Fair value included in ‘Financial instruments sold, not yet purchased, at fair value’				$	34.3					$	30.7


	-1	As of December 31, 2013 and September 30, 2013, the Company’s derivative contract volume for open positions were approximately 3.0 million and 4.1 million contracts, respectively.
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block]	'
	The following table sets forth the Company’s gains (losses) related to derivative financial instruments for the three months ended December 31, 2013 and 2012, in accordance with the Derivatives and Hedging Topic of the ASC. The gains (losses) set forth below are included in ‘trading gains, net’ in the condensed consolidated income statements.


		Three Months Ended December 31,
	(in millions)	2013			2012
	Commodities	$	8.7		$	30.6

	Foreign exchange	2.1			2.6

	Interest rate	—			0.1

	Net gains (losses) from derivative contracts	$	10.8		$	33.3

Physical_Commodities_Inventory1

Physical Commodities Inventory (Tables)	3 Months Ended
	Dec. 31, 2013
Physical Commodities Inventory [Abstract]	'
Schedule of Inventory, Current [Table Text Block]	'
	The carrying values of the Company’s inventory as of December 31, 2013 and September 30, 2013 are shown below.


	(in millions)	December 31,		September 30, 2013
		2013
	Physical commodities inventory - finished commodities	$	26.6	$	59

Goodwill_Tables

Goodwill (Tables)	3 Months Ended
	Dec. 31, 2013
Goodwill [Abstract]	'
Schedule of Goodwill [Table Text Block]	'
	The carrying value of goodwill by segment is as follows:


	(in millions)	December 31,		September 30,
		2013		2013
	Commodity and Risk Management Services	$	33.1	$	33.1

	Foreign Exchange	6.3		6.3

	Securities	8.1		8.1

	Goodwill	$	47.5	$	47.5

Intangible_Assets_Tables

Intangible Assets - (Tables)	3 Months Ended
	Dec. 31, 2013
Intangible Assets [Abstract]	'
Schedule of Finite and Indefinite-Lived Intangible Assets [Table Text Block]	'
	The gross and net carrying values of intangible assets as of the balance sheet dates, by major intangible asset class are as follows:


		December 31, 2013							September 30, 2013
	(in millions)	Gross Amount		Accumulated			Net Amount		Gross Amount		Accumulated			Net Amount
				Amortization							Amortization
	Intangible assets subject to amortization
	Noncompete agreement	$	—	$	—		$	—	$	3.7	$	(3.7	)	$	—

	Trade name	—		—			—		0.7		(0.7		)	—

	Software programs/platforms	2.2		(1.6		)	0.6		2.2		(1.5		)	0.7

	Customer base	12.4		(2.8		)	9.6		12.4		(2.6		)	9.8

		14.6		(4.4		)	10.2		19		(8.5		)	10.5

	Intangible assets not subject to amortization
	Trade name	1.1		—			1.1		1.1		—			1.1

	Total intangible assets	$	15.7	$	(4.4	)	$	11.3	$	20.1	$	(8.5	)	$	11.6

Schedule of Expected Amortization Expense [Table Text Block]	'
	Amortization expense related to intangible assets was $0.3 million and $0.6 million for the three months ended December 31, 2013 and 2012, respectively.
	As of December 31, 2013, the estimated future amortization expense was as follows:


	(in millions)
	Fiscal 2014 (remaining nine months)	$	1

	Fiscal 2015	1.1

	Fiscal 2016	0.7

	Fiscal 2017	0.7

	Fiscal 2018	0.7

	Fiscal 2019 and thereafter	6

		$	10.2

Credit_Facilities_Tables

Credit Facilities (Tables)	3 Months Ended
	Dec. 31, 2013
Credit Facilities [Abstract]	'
Schedule of Debt [Table Text Block]	'
	The following table sets forth a listing of credit facilities, the committed amounts as of December 31, 2013 on the facilities, and outstanding borrowings on the facilities as well as indebtedness on senior notes as of December 31, 2013 and September 30, 2013:


	(in millions)
	Credit Facilities						Amounts Outstanding
		Borrower	Security	Renewal / Expiration Date	Total Commitment		December 31,		September 30,
							2013		2013
		INTL FCStone Inc.	Certain pledged shares	September 20, 2016	$	140	$	49	$	55

		FCStone, LLC	None	April 10, 2014	75		—		—

		FCStone Merchants	Certain commodities assets	May 1, 2014	75		11.2		6

		INTL FCStone, Ltd.	None	November 10, 2014	25		—		—

					$	315	$	60.2	$	61

	Senior Unsecured Notes
		8.50% senior notes, due July 30, 2020					45.5		45.5

	Total indebtedness						$	105.7	$	106.5

Capital_and_Other_Regulatory_R1

Capital and Other Regulatory Requirements (Tables)	3 Months Ended
	Dec. 31, 2013
Capital and Other Regulatory Requirements [Abstract]	'
Regulatory Capital Requirements under Banking Regulations [Text Block]	'
	Capital and Other Regulatory Requirements
	The Company’s activities are subject to significant governmental regulation, both in the United States and overseas. The subsidiaries of the Company were in compliance with all of their regulatory requirements as of December 31, 2013, as follows:


	(in millions)			As of December 31, 2013
	Subsidiary	Regulatory Authority	Requirement Type	Actual		Minimum
						Requirement
	FCStone, LLC	CFTC	Net capital	$	106.9	$	63.3

	FCStone, LLC	CFTC	Segregated funds	$	1,606.10	$	1,582.70

	FCStone, LLC	CFTC	Secured funds	$	69	$	52.4

	INTL FCStone Ltd	FCA (United Kingdom)	Net capital	$	59.7	$	25.8

	INTL FCStone Ltd	FCA (United Kingdom)	Segregated funds	$	65.4	$	64.2

	INTL Global Currencies Limited	FCA (United Kingdom)	Net capital	$	20.5	$	0.5

	INTL FCStone Securities Inc.	SEC	Net capital	$	4.8	$	1

	FCC Investments, Inc.	SEC	Net capital	$	0.3	$	0.3

	FCStone Australia	Australian Securities and Investment Commission	Net capital	$	1.7	$	0.9

	FCStone Australia	New Zealand Clearing Ltd	Capital adequacy	$	11.5	$	4.1

	INTL FCStone DTVM Ltda.	Brazilian Central Bank and Securities and Exchange Commission of Brazil	Capital adequacy	$	1	$	0.6

	INTL Capital S.A.	Rosario Futures Exchange (Argentina)	Capital adequacy	$	5.7	$	0.1

	INTL Capital S.A.	General Inspector of Justice (Argentina)	Net capital	$	7.6	$	6.7

	INTL CIBSA Sociedad de Bolsa S.A.	Superintendent of Securities Markets of Buenos Aires (Argentina)	Net capital	$	6.4	$	0.2

	Certain other non-U.S. subsidiaries of the Company are also subject to capital adequacy requirements promulgated by authorities of the countries in which they operate. As of December 31, 2013, these subsidiaries were in compliance with their local capital adequacy requirements.

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	3 Months Ended
	Dec. 31, 2013
Stock-Based Compensation [Abstract]	'
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	'
	The following is a summary of stock option activity for the three months ended December 31, 2013:


		Shares		Number of		Weighted		Weighted				Weighted	Aggregate
		Available for		Options		Average Price		Average				Average	Intrinsic
		Grant		Outstanding				Grant Date				Remaining	Value
								Fair Value				Term	($ millions)
												(in years)
	Balances as of September 30, 2013	1,000,000		1,779,983		$	24.76	$	11.44			4.87	$	4.8

	Granted	—		—		$	—	$	—

	Exercised			(44,920	)	$	12.05	$	6.22

	Forfeited	—		—		$	—	$	—

	Expired	—		(32,647	)	$	50.64	$	14.27

	Balances as of December 31, 2013	1,000,000		1,702,416		$	24.6	$	11.52			4.81	$	3.3

	Exercisable as of December 31, 2013			761,103		$	23.91	$	9.75			1.73	$	3.3

Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]	'
	The following is a summary of restricted stock activity for the three months ended December 31, 2013:


		Shares		Number of		Weighted		Weighted		Aggregate
		Available for		Shares		Average		Average		Intrinsic
		Grant		Outstanding		Grant Date		Remaining		Value
						Fair Value		Term		($ millions)
								(in years)
	Balances as of September 30, 2013	1,154,862		363,638		$	20.53	1.74		$	7.4

	Granted	(47,423	)	47,423		$	20.35

	Vested			(102,581	)	$	19.76

	Forfeited	30,811		(54,447	)	$	21.68

	Balances as of December 31, 2013	1,138,250		254,033		$	20.55	2.01		$	4.7

Other_Expenses_Tables

Other Expenses (Tables)	3 Months Ended
	Dec. 31, 2013
Other Expenses [Abstract]	'
Schedule of Other Operating Cost and Expense, by Component [Table Text Block]	'
	Other expenses for the three months ended December 31, 2013 and 2012 consisted of the following:


		Three Months Ended December 31,
	(in millions)	2013		2012
	Contingent consideration, net(1)	$	0.2	$	0.7

	Insurance	0.5		0.5

	Advertising, meetings and conferences	0.4		0.4

	Non-trading hardware and software maintenance and software licensing	0.7		0.6

	Office supplies and printing	0.3		0.3

	Other clearing related expenses	0.4		0.4

	Other non-income taxes	1		1.1

	Other	1.2		2.6

	Total other expenses	$	4.7	$	6.6


	-1	Contingent consideration includes remeasurement of contingent liabilities related to business combinations accounted for in accordance with the provisions of the Business Combinations Topic of the ASC (see Note 3).

Segment_Analysis_Tables

Segment Analysis (Tables)	3 Months Ended
	Dec. 31, 2013
Segment Analysis [Abstract]	'
Schedule of Segment Reporting Information, by Segment [Table Text Block]	'
	Information concerning operations in these segments of business is shown in accordance with the Segment Reporting Topic of the ASC as follows:


		Three Months Ended December 31,
	(in millions)	2013				2012
	Total revenues:
	Commodity and Risk Management Services	$	7,766.90			$	12,453.10

	Foreign Exchange	18.3				16.2

	Securities	17.6				12.9

	Clearing and Execution Services	23.8				22.4

	Other	111.8				39.5

	Corporate unallocated	(0.4		)		8.7

	Total	$	7,938.00			$	12,552.80

	Operating revenues (loss):
	Commodity and Risk Management Services	$	48.5			$	60.7

	Foreign Exchange	18.3				16.2

	Securities	17.6				12.9

	Clearing and Execution Services	23.8				22.4

	Other	5.6				4.8

	Corporate unallocated	(0.4		)		8.7

	Total	$	113.4			$	125.7

	Net contribution:
	(Revenues less cost of sales, transaction-based clearing expenses, variable bonus compensation, introducing broker commissions and interest expense)
	Commodity and Risk Management Services	$	29.2			$	40.5

	Foreign Exchange	12.1				10.4

	Securities	8.6				6.9

	Clearing and Execution Services	3.7				3.6

	Other	4.1				2.8

	Total	$	57.7			$	64.2

	Segment income (loss):
	(Net contribution less non-variable direct segment costs)
	Commodity and Risk Management Services	$	13.1			$	22.7

	Foreign Exchange	8.1				7.1

	Securities	4.3				3.2

	Clearing and Execution Services	1.1				(0.9		)

	Other	2.9				1.9

	Total	$	29.5			$	34

Reconciliation of segment income to income from operations, before tax:
Segment income	$	29.5			$	34

Costs not allocated to operating segments	25.5				15.2

Income from operations, before tax	$	4			$	18.8


(in millions)	As of December 31, 2013				As of September 30, 2013
Total assets:
Commodity and Risk Management Services	$	1,057.20			$	1,105.10

Foreign Exchange	126.8				145

Securities	226.6				198.5

Clearing and Execution Services	1,164.80				1,246.40

Other	54.7				37.3

Corporate unallocated	113.8				115.7

Total	$	2,743.90			$	2,848.00

Basis_of_Presentation_and_Cons2

Basis of Presentation and Consolidation and Recently Issued Accounting Standards (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Revenues	$7,938	$12,552.80
Cost of sales of physical commodities	7,824.60	12,427.10
Number of different types of foreign currencies	130	'
Number of accounts for customers company-wide	20,000	'
Number of customers company-wide	11,000	'
Scenario, Adjustment [Member]	'	'
Revenues	'	166.7
Cost of sales of physical commodities	'	166.7
Scenario, Previously Reported [Member]	'	'
Revenues	'	12,719.50
Cost of sales of physical commodities	'	12,593.80
Restatement Adjustment [Member]	'	'
Revenues	'	12,552.80
Cost of sales of physical commodities	'	$12,427.10

Earnings_per_Share_Antidulitiv

Earnings per Share - Antidulitive Securities (Details)	3 Months Ended
Earnings per Share - Antidulitive Securities (Details)	Dec. 31, 2013	Dec. 31, 2012
Note 2 b Earnings per Share [Abstract]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,126,282	1,490,547

Earnings_per_Share_EPS_Reconci

Earnings per Share - EPS Reconciliation (Details) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]	'	'
Net income	$2.50	$13.30
Less: Allocation to participating securities	-0.1	-0.5
Income from continuing operations allocated to common stockholders	2.4	12.8
Diluted net income	2.5	13.3
Less: Allocation to participating securities	-0.1	-0.5
Diluted net income allocated to common stockholders	$2.40	$12.80
Weighted average number of common shares outstanding	18,657,678	18,266,338
Weighted average number of dilutive potential common shares outstanding - Share-based awards	700,764	512,337
Weighted average number of diluted shares	19,358,442	18,778,675

Assets_and_Liabilities_at_Fair2

Assets and Liabilities, at Fair Value Assets and Liabilities, at Fair Value - Financial Instruments at Fair Value Disclosure (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'	'
Long-term Debt, Fair Value	$46.20	'
Senior Notes	$45.50	$45.50

Assets_and_Liabilities_at_Fair3

Assets and Liabilities, at Fair Value - Financial Assets and Liabilities Measured at Fair Value (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	$215	$449.40
Deposits and receivables from exchange-clearing organizations	1,706.10	1,576.60
Deposits and receivables from brokers-dealers, clearing organizations and counterparties	163.9	168.3
Financial instruments, owned	169	158.5
Total assets at fair value	1,554	1,627.70
Accounts payable and other accrued liabilities	98.6	114
Payables to customers	1,983.10	2,091.80
Financial instruments sold, not yet purchased, at fair value	211.4	179.9
Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	3.1	3
Securities and other assets segregated under federal and other regulations	33.5	107.6
Deposits and receivables from exchange-clearing organizations	1,353.50	1,371.70
Deposits and receivables from brokers-dealers, clearing organizations and counterparties	-5.1	-13.1
Financial instruments, owned	169	158.5
Total assets at fair value	1,554	1,627.70
Financial instruments sold, not yet purchased, at fair value	211.4	179.9
Total liabilities at fair value	220.5	189.5
Fair Value, Measurements, Recurring [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Payables to customers	0	0
Fair Value, Measurements, Recurring [Member] \| Contingent consideration, net [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Accounts payable and other accrued liabilities	9.1	9.6
Fair Value, Measurements, Recurring [Member] \| Common stock and American Depositary Receipts (ADRs) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	78.8	69.8
Financial instruments sold, not yet purchased, at fair value	102.8	99.5
Fair Value, Measurements, Recurring [Member] \| Exchangeable foreign ordinary equities and ADRs [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	28.8	36.7
Financial instruments sold, not yet purchased, at fair value	15	8.7
Fair Value, Measurements, Recurring [Member] \| Corporate Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	20.6	3.6
Financial instruments sold, not yet purchased, at fair value	15.9	'
Fair Value, Measurements, Recurring [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0.3	0.3
Fair Value, Measurements, Recurring [Member] \| Foreign Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	9.8	7.7
Fair Value, Measurements, Recurring [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	18.6	21.9
Financial instruments sold, not yet purchased, at fair value	34.3	30.7
Fair Value, Measurements, Recurring [Member] \| Commodities leases and unpriced positions [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0.7	6.1
Financial instruments sold, not yet purchased, at fair value	43.4	41
Fair Value, Measurements, Recurring [Member] \| Commodities warehouse receipts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	'	4
Fair Value, Measurements, Recurring [Member] \| Exchange firm common stock [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	4.7	4.4
Fair Value, Measurements, Recurring [Member] \| Mutual funds and other [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	5.2	4
Fair Value, Measurements, Recurring [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	1.5	'
Fair Value, Measurements, Recurring [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	776.8	841.4
Fair Value, Measurements, Recurring [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	590	594.8
Fair Value, Measurements, Recurring [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	3.5	5.3
Fair Value, Measurements, Recurring [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	-16.8	-69.8
Fair Value, Measurements, Recurring [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	'	75
Fair Value, Measurements, Recurring [Member] \| Commodities warehouse receipts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	14.5	13.1
Fair Value, Measurements, Recurring [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	19	19.5
Fair Value, Measurements, Recurring [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	0.1	0.1
Fair Value, Measurements, Recurring [Member] \| Certificates of Deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	3	2.9
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	3.1	3
Securities and other assets segregated under federal and other regulations	14.5	88.1
Deposits and receivables from exchange-clearing organizations	2,354	3,104.60
Deposits and receivables from brokers-dealers, clearing organizations and counterparties	0.3	1.8
Financial instruments, owned	274.4	279.8
Total assets at fair value	2,646.30	3,477.30
Financial instruments sold, not yet purchased, at fair value	274.1	265.6
Total liabilities at fair value	1,768.20	2,593.80
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Payables to customers	1,494.10	2,328.20
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Contingent consideration, net [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Accounts payable and other accrued liabilities	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Common stock and American Depositary Receipts (ADRs) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	62.3	49.3
Financial instruments sold, not yet purchased, at fair value	91.5	82.9
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Exchangeable foreign ordinary equities and ADRs [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	28.8	36.7
Financial instruments sold, not yet purchased, at fair value	15	8.7
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Corporate Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	17.2	0.1
Financial instruments sold, not yet purchased, at fair value	15.7	'
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Foreign Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	9.8	7.7
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	146.4	173.6
Financial instruments sold, not yet purchased, at fair value	151.9	174
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Commodities leases and unpriced positions [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Commodities warehouse receipts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	'	4
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Exchange firm common stock [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	4.7	4.4
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Mutual funds and other [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	5.2	4
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	'
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	776.8	841.4
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	1,577.20	2,263.20
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	'	75
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Commodities warehouse receipts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	14.5	13.1
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	0.1	0.1
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Certificates of Deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	3	2.9
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	0	0
Securities and other assets segregated under federal and other regulations	19	19.5
Deposits and receivables from exchange-clearing organizations	593.5	600.1
Deposits and receivables from brokers-dealers, clearing organizations and counterparties	0.9	0.2
Financial instruments, owned	611.8	516.8
Total assets at fair value	1,225.20	1,136.60
Financial instruments sold, not yet purchased, at fair value	636.1	575.3
Total liabilities at fair value	636.1	575.3
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Payables to customers	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Contingent consideration, net [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Accounts payable and other accrued liabilities	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Common stock and American Depositary Receipts (ADRs) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	15.8	19.8
Financial instruments sold, not yet purchased, at fair value	11.3	16.6
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Exchangeable foreign ordinary equities and ADRs [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Corporate Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Financial instruments sold, not yet purchased, at fair value	0.2	'
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0.3	0.3
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Foreign Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	553.8	440.6
Financial instruments sold, not yet purchased, at fair value	542.4	473.2
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Commodities leases and unpriced positions [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	40.4	56.1
Financial instruments sold, not yet purchased, at fair value	82.2	85.5
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Commodities warehouse receipts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	'	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Exchange firm common stock [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Mutual funds and other [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	1.5	'
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	590	594.8
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	3.5	5.3
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	'	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Commodities warehouse receipts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	19	19.5
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Certificates of Deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	0	0
Securities and other assets segregated under federal and other regulations	0	0
Deposits and receivables from exchange-clearing organizations	0	0
Deposits and receivables from brokers-dealers, clearing organizations and counterparties	0	0
Financial instruments, owned	4.1	4.2
Total assets at fair value	4.1	4.2
Financial instruments sold, not yet purchased, at fair value	0	0
Total liabilities at fair value	9.1	9.6
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Payables to customers	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Contingent consideration, net [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Accounts payable and other accrued liabilities	9.1	9.6
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Common stock and American Depositary Receipts (ADRs) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0.7	0.7
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Exchangeable foreign ordinary equities and ADRs [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Corporate Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	3.4	3.5
Financial instruments sold, not yet purchased, at fair value	0	'
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Foreign Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Commodities leases and unpriced positions [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Commodities warehouse receipts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	'	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Exchange firm common stock [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Mutual funds and other [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	'
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	'	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Commodities warehouse receipts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Certificates of Deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	0	0
Securities and other assets segregated under federal and other regulations	0	0
Deposits and receivables from exchange-clearing organizations	-1,594	-2,333
Deposits and receivables from brokers-dealers, clearing organizations and counterparties	-6.3	-15.1
Financial instruments, owned	-721.3	-642.3
Total assets at fair value	-2,321.60	-2,990.40
Financial instruments sold, not yet purchased, at fair value	-698.8	-661
Total liabilities at fair value	-2,192.90	-2,989.20
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Payables to customers	-1,494.10	-2,328.20
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Contingent consideration, net [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Accounts payable and other accrued liabilities	0	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Common stock and American Depositary Receipts (ADRs) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Exchangeable foreign ordinary equities and ADRs [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Corporate Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	'
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Foreign Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	-681.6	-592.3
Financial instruments sold, not yet purchased, at fair value	-660	-616.5
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Commodities leases and unpriced positions [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	-39.7	-50
Financial instruments sold, not yet purchased, at fair value	-38.8	-44.5
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Commodities warehouse receipts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	'	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Exchange firm common stock [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Mutual funds and other [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial instruments, owned	0	'
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	0	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	0	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	0	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Derivative [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Deposits and receivables from exchange-clearing organizations	-1,594	-2,333
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	'	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Commodities warehouse receipts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	0	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities and other assets segregated under federal and other regulations	0	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] \| Netting [Member] \| Certificates of Deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Unrestricted cash equivalents	$0	$0

Assets_and_Liabilities_at_Fair4

Assets and Liabilities, at Fair Value - Details of Level 3 Assets and Liabilities (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Assets and Liabilities, at Fair Value [Abstract]	'	'
Total Level 3 Assets	$4.10	$4.20
Level 3 assets for which the company bears economic exposure	4.1	4.2
Assets	2,743.90	2,848
Total assets at fair value	$1,554	$1,627.70
Total level 3 assets as a percentage of total assets	0.10%	0.10%
Level 3 assets for which the company bears economic exposure as a percertange of total assets	0.10%	0.10%
Total level 3 assets as a percentage of total financial assets at fair value	0.30%	0.30%

Assets_and_Liabilities_at_Fair5

Assets and Liabilities, at Fair Value - Rollforward of Level 3 (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Rollforward of Level 3 Securities [Roll Forward]	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$4.20	$4.50
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	-0.1	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	4.1	4.5
Contingent Consideration [Member]	'	'
Rollforward of Level 3 Liabilities [Roll Forward]	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	9.6	14.8
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease)	0.2	0.3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	0	3.1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	-0.7	-0.3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	9.1	17.9
Common stock and American Depositary Receipts (ADRs) [Member]	'	'
Rollforward of Level 3 Securities [Roll Forward]	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	0.7	0.9
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	0.7	0.9
Corporate Debt Securities [Member]	'	'
Rollforward of Level 3 Securities [Roll Forward]	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	3.5	3.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	-0.1	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$3.40	$3.60

Assets_and_Liabilities_at_Fair6

Assets and Liabilities, at Fair Value Assets and Liabilities, at Fair Value - Suriwongse Bonds (Details) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Suriwongse Debt Investment Balance	$3.40

Assets_and_Liabilities_at_Fair7

Assets and Liabilities, at Fair Value - Contingent Consideration (Details) (Contingent Consideration [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Contingent Consideration [Member]	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease)	$0.20	$0.30

Assets_and_Liabilities_at_Fair8

Assets and Liabilities, at Fair Value - Available for Sale Securities in OCI (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2013	Sep. 30, 2013
Assets and Liabilities, at Fair Value [Abstract]	'	'	'
Equity Investments in Exchange Stock - Cost	'	$3.70	$3.70
Exchange firm common stock	'	4.7	4.4
Proceeds from Sale of Available-for-sale Securities	8.6	'	'
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax - LME Shares	6.3	'	'
Deferred Tax Liabilities, Accumulated Other Comprehensive Income - LME Shares	2	'	'
Proceeds from Shares of Exchanges Sold	1.5	'	'
Gain (Loss) on Sale of Exchange Shares	0.9	'	'
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	'	0.7	0.5
Deferred Taxes, Accumulated Other Comprehensive Income - AFS	'	($0.40)	($0.30)

Assets_and_Liabilities_at_Fair9

Assets and Liabilities, at Fair Value - Available for Sale Securities - Dep and Rec (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale Debt Securities, Amortized Cost Basis	$567.70	$573.70
Available-for-sale Securities, Gross Unrealized Gains	0.2	0.1
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities, Debt Securities	567.9	573.8
Deposits and receivables from exchange clearing organizations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale Securities, Gross Unrealized Gain (Loss)	'	0.1
US Government Debt Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale Debt Securities, Amortized Cost Basis	562.8	568.5
Available-for-sale Securities, Gross Unrealized Gains	0.1	0
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities, Debt Securities	562.9	568.5
Collateralized Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale Debt Securities, Amortized Cost Basis	4.9	5.2
Available-for-sale Securities, Gross Unrealized Gains	0.1	0.1
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities, Debt Securities	$5	$5.30

Recovered_Sheet1

Assets and Liabilities, at Fair Value - Available for Sale Securities (Maturities) (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	$562.90	$568.50
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value	5	5.3
Available-for-sale Securities, Debt Securities	567.9	573.8
US Government Debt Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	562.9	568.5
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value	0	0
Available-for-sale Securities, Debt Securities	562.9	568.5
Collateralized Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	0	0
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value	5	5.3
Available-for-sale Securities, Debt Securities	$5	$5.30

Financial_Instruments_with_Off2

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Obligations to Purchase Financial Instruments at a Future Date (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk [Abstract]	'	'
Financial instruments sold, not yet purchased, at fair value	$211.40	$179.90

Financial_Instruments_with_Off3

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Gross Derivative Assets and Liabilities by Type and Balance Sheet Location (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	$2,278.60	$2,879.40
Derivative Liability, Fair Value, Gross Liability	2,188.40	2,975.40
Derivative Asset, Fair Value, Amount Offset Against Collateral	-2,281.90	-2,940.40
Derivative Liability, Fair Value, Amount Offset Against Collateral	-2,154.10	-2,944.70
Exchange-traded Commodity Contracts [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	1,430	2,036.60
Derivative Liability, Fair Value, Gross Liability	1,311	2,046.30
Over the Counter (OTC) Commodity Contracts [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	411.9	481.4
Derivative Liability, Fair Value, Gross Liability	419.9	484.9
Foreign Exchange Forward [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	75.3	89.3
Derivative Liability, Fair Value, Gross Liability	77.9	104.2
Over the Counter (OTC) Foreign Exchange Contracts [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	287.7	132.3
Derivative Liability, Fair Value, Gross Liability	274.4	162.3
Exchange-traded interest rate contracts [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	8.6	4.3
Derivative Liability, Fair Value, Gross Liability	3.9	36
Equity Contract [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	65.1	135.5
Derivative Liability, Fair Value, Gross Liability	101.3	141.7
Deposits and receivables from exchange clearing organizations [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative, Fair Value, Net	-16.8	-69.8
Deposits and receivables from broker-dealers, clearing organizations and counterparties [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative, Fair Value, Net	-5.1	-13.1
Financial instruments owned [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative, Fair Value, Net	18.6	21.9
Financial instrument sold, not yet purchased [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative, Fair Value, Net	$34.30	$30.70

Financial_Instruments_with_Off4

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Derivatives Volume (Details)	Dec. 31, 2013	Sep. 30, 2013
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk [Abstract]	'	'
Derivative, Number of Instruments Held	3,000,000	4,100,000

Financial_Instruments_with_Off5

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Realized Gains/Losses on Derivative Contracts (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Commodity Contract [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$8.70	$30.60
Foreign Exchange Forward [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Derivative Instruments, Gain (Loss) Recognized in Income, Net	2.1	2.6
Interest Rate Contract [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Derivative Instruments, Gain (Loss) Recognized in Income, Net	0	0.1
Derivative [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$10.80	$33.30

Receivables_From_Customers_Net2

Receivables From Customers, Net and Notes Receivable, Net - Allowance for Customer Receivables (Details) (USD $)	3 Months Ended		3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
	Dec. 31, 2013	Sep. 30, 2013	Commodity and Risk Management [Member]	Commodity and Risk Management [Member]
Receivables from customers and notes receivable, net [Abstract]	'	'	'	'
Allowance for Doubtful Accounts Receivable	$1.40	$1.10	'	'
Statement [Line Items]	'	'	'	'
Provision for Doubtful Accounts	0.3	'	0.4	0.4
Allowance for Doubtful Accounts Receivable, Charge-offs	'	'	$0.10	'

Receivables_From_Customers_Net3

Receivables From Customers, Net and Notes Receivable, Net - Allowance for Notes Receivable (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Receivables from customers and notes receivable, net [Abstract]	'	'
Allowance Notes Receivable	$0.10	$0.10

Receivables_From_Customers_Net4

Receivables From Customers, Net and Notes Receivable, Net - Exim Bank Notes Receivable (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Insured short-term notes receivable	$17.30	$21.10
Obligations for participation rights	$16	$18.70
Minimum [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Short Term Notes Receivable Outstanding Balance Threshold, Percentage	90.00%	'
Maximum [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Short Term Notes Receivable Outstanding Balance Threshold, Percentage	98.00%	'

Physical_Commodities_Inventory2

Physical Commodities Inventory - Physical Commodities Inventory by CIP and Finished (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Physical Commodities Inventory [Abstract]	'	'
Physical commodities inventory	$26.60	$59

Physical_Commodities_Inventory3

Physical Commodities Inventory - LCM Adjustments (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Note 6 b Physical Commodities Inventory [Abstract]	'	'
Inventory Adjustments	$0.30	$0.90

Goodwill_Goodwill_by_Segment_D

Goodwill - Goodwill by Segment (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Goodwill [Line Items]	'	'
Goodwill	$47.50	$47.50
Commodity and Risk Management [Member]	'	'
Goodwill [Line Items]	'	'
Goodwill	33.1	33.1
Foreign Exchange [Member]	'	'
Goodwill [Line Items]	'	'
Goodwill	6.3	6.3
Securities [Member]	'	'
Goodwill [Line Items]	'	'
Goodwill	$8.10	$8.10

Intangible_Assets_Gross_and_Ne

Intangible Assets - Gross and Net Intangible Assets by Major Class (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Finite-Lived Intangible Assets, Gross	$14.60	$19
Finite-Lived Intangible Assets, Accumulated Amortization	-4.4	-8.5
Finite-Lived Intangible Assets, Net	10.2	10.5
Noncompete Agreements [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Finite-Lived Noncompete Agreements, Gross	0	3.7
Finite-Lived Intangible Assets, Accumulated Amortization	0	-3.7
Finite-Lived Intangible Assets, Net	0	0
Trade Names [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Finite-Lived Trade Names, Gross	0	0.7
Finite-Lived Intangible Assets, Accumulated Amortization	0	-0.7
Finite-Lived Intangible Assets, Net	0	0
Computer Software, Intangible Asset [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Finite-Lived Computer Software, Gross	2.2	2.2
Finite-Lived Intangible Assets, Accumulated Amortization	-1.6	-1.5
Finite-Lived Intangible Assets, Net	0.6	0.7
Customer Relationships [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Finite-Lived Customer Lists, Gross	12.4	12.4
Finite-Lived Intangible Assets, Accumulated Amortization	-2.8	-2.6
Finite-Lived Intangible Assets, Net	$9.60	$9.80

Intangible_Assets_IndefiniteLi

Intangible Assets - Indefinite-Lived Intangible Assets (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013
Indefinite-lived Intangible Assets [Line Items]	'	'	'
Gross Finite and Indefinite-Lived Intangible Assets	$15.70	'	$20.10
Finite and Indefinited-Lived Accumulated Amortization and Impairment Charges	-4.4	'	-8.5
Intangible Assets, Net (Excluding Goodwill)	11.3	'	11.6
Trade Names [Member]	'	'	'
Indefinite-lived Intangible Assets [Line Items]	'	'	'
Indefinite-Lived Trade Names	1.1	'	1.1
Indefinite-lived Intangible Assets, Impairment Losses	$0	$0	'

Intangible_Assets_FiniteLived_

Intangible Assets - Finite-Lived Intangible Assets Future Amortization Expense (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013
Intangible Assets [Abstract]	'	'	'
Amortization of Intangible Assets	$0.30	$0.60	'
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]	'	'	'
Fiscal 2013, Remainder of Fiscal Year	1	'	'
Fiscal 2014	1.1	'	'
Fiscal 2015	0.7	'	'
Fiscal 2016	0.7	'	'
Fiscal 2017	0.7	'	'
Fiscal 2018 and thereafter	6	'	'
Finite-Lived Intangible Assets, Net	$10.20	'	$10.50

Credit_Facilities_Number_of_Cr

Credit Facilities - Number of Credit Facilities (Details)	Dec. 31, 2013
Credit Facilities [Abstract]	'
Number of credit facilities	4

Credit_Facilities_Credit_Facil

Credit Facilities - Credit Facilities (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2013
Line of Credit Facility [Line Items]	'	'
Senior Notes	$45.50	$45.50
Debt Instrument, Interest Rate, Stated Percentage	'	8.50%
Debt Instrument, Call Feature, Redemption Price Percentage of Principal	'	100.00%
Debt Issuance Cost	1.7	'
Line of Credit Facility, Amount Outstanding	61	60.2
Debt and Capital Lease Obligations	106.5	105.7
Main line of credit facilities [Member]	'	'
Line of Credit Facility [Line Items]	'	'
Line of Credit Facility, Maximum Borrowing Capacity	'	315
Line of Credit Facility, Current Borrowing Capacity	'	175
HCO Syndicated line of credit facility [Member]	'	'
Line of Credit Facility [Line Items]	'	'
Line of Credit Facility, Maximum Borrowing Capacity	'	140
Line of Credit Facility, Amount Outstanding	55	49
FCS Margin line of credit facility [Member]	'	'
Line of Credit Facility [Line Items]	'	'
Line of Credit Facility, Maximum Borrowing Capacity	'	75
Line of Credit Facility, Amount Outstanding	0	0
FMS Sub-note commodity line of credit facility [Member]	'	'
Line of Credit Facility [Line Items]	'	'
Line of Credit Facility, Maximum Borrowing Capacity	'	75
Line of Credit Facility, Amount Outstanding	6	11.2
INTL FCStone, Ltd [Member]	'	'
Line of Credit Facility [Line Items]	'	'
Line of Credit Facility, Maximum Borrowing Capacity	'	25
Line of Credit Facility, Amount Outstanding	$0	$0

Commodity_and_Other_Repurchase1

Commodity and Other Repurchase Agreements Commodity and Other Repurchase Agreements (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Assets Sold under Agreements to Repurchase [Line Items]	'	'
Financing Receivables, net - Sales/Repurchase Agreements	$22	$9.20
Lenders Under Loans [Member]	'	'
Assets Sold under Agreements to Repurchase [Line Items]	'	'
Obligations outstanding related to commodities sold under repurchase agreements	$11.20	$6

Commitments_and_Contingencies_2

Commitments and Contingencies - Contingencies and Litigation (Details) (USD $)	3 Months Ended
	Dec. 31, 2013
Loss Contingency, Settlement Agreement, Consideration	$265,000
Excess segregated funds returned	15,500,000
Excess segregated funds invested	21,900,000
Pre and Post Transfers of Funds related to Sentinel	15,500,000
Customer Segregated Transfers of Funds Pursuant to Safe Harbor	1,100,000
Sentinel Appeal Cash Deposit	8,000,000
Maximum [Member]	'
Excess segregated funds returned	6,000,000
Minimum [Member]	'
Excess segregated funds returned	$4,000,000

Commitments_and_Contingencies_3

Commitments and Contingencies - Contigent Consideration for Acquisitions (Details) (USD $)	3 Months Ended			3 Months Ended						3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Nov. 30, 2011	Dec. 31, 2013	Dec. 31, 2012
	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Tradewire Acquisition [Member] [Member]	Hencorp Acquisition [Member]	Tradewire Acquisition [Member] [Member]	Hencorp Acquisition [Member]	Coffee Network Acquisition [Member]	Coffee Network Acquisition [Member]	Contingent Consideration [Member]	Contingent Consideration [Member]
Business Acquisition, Contingent Consideration [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Accounts payable and other accrued liabilities - contingent consideration, fair value	$9.10	'	$9.60	'	'	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease)	'	'	'	'	'	'	'	'	'	0.2	0.3
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	0.2	3.4	'	0.2	0.1	'	'	'	'	'	'
Business Combination, Consideration, Including Contingent Consideration	'	'	'	'	'	6.6	'	'	'	'	'
Business Acquisition, Cost of Acquired Entity, Purchase Price	'	'	'	'	'	'	7.5	0.1	'	'	'
Business Acquisition, Contingent Consideration, at Fair Value	'	'	'	'	$2.50	'	'	'	$0.10	'	'

Capital_and_Other_Regulatory_R2

Capital and Other Regulatory Requirements - Regulatory Capital Requirements (Details) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2013
FCStone LLC [Member]	'
Net Capital under Commodity Exchange Act Computation	$106.90
Required Net Capital under Commodity Exchange Act	63.3
Cash and Securities Segregated under Commodity Exchange Act Regulation	1,606.10
Cash and Securities Segregated under Commodity Exchange Act Regulation, Amount Required to be Segregated	1,582.70
Secured Funds	69
Secured Funds Required Under Commodity Exchange Act	52.4
INTL FCStone Europe [Member]	'
Net Capital under Commodity Exchange Act Computation	59.7
Required Net Capital under Commodity Exchange Act	25.8
Net Capital	65.4
Cash and Securities Segregated under Commodity Exchange Act Regulation	64.2
INTL Global Currencies [Member]	'
Net Capital under Commodity Exchange Act Computation	20.5
Required Net Capital under Commodity Exchange Act	0.5
INTL Trading [Member]	'
Net Capital	4.8
Minimum Net Capital Required for Entity	1
FCC Investments [Member]	'
Net Capital	0.3
Minimum Net Capital Required for Entity	0.3
FCStone Australia [Member]	'
Net Capital under Commodity Exchange Act Computation	1.7
Required Net Capital under Commodity Exchange Act	0.9
Net Capital	11.5
Capital Required for Capital Adequacy	4.1
INTL FCStone DTVM Ltda [Member]	'
Net Capital	1
Capital Required for Capital Adequacy	0.6
INTL Capital S.A b Rosario Futures Exchanges [Member] [Domain]	'
Net Capital	5.7
Capital Required for Capital Adequacy	0.1
INTL Capital S.A. b General Inspector of Justice [Member] [Domain]	'
Net Capital under Commodity Exchange Act Computation	7.6
Required Net Capital under Commodity Exchange Act	6.7
INTL Capital S.A. b Superintendence of Securities Markets of Buenos Aires [Member] [Domain]	'
Net Capital under Commodity Exchange Act Computation	6.4
Required Net Capital under Commodity Exchange Act	$0.20

StockBased_Compensation_Stockb

Stock-Based Compensation - Stock-based Compensation Expense (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Note 13 b Stock-Based Compensation [Abstract]	'	'
Allocated Share-based Compensation Expense	$1.10	$1.60

StockBased_Compensation_Stock_

Stock-Based Compensation - Stock Option Plan (Details)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
Stock-Based Compensation [Abstract]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	'	'	1,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,000,000	1,000,000	'

StockBased_Compensation_Stock_1

Stock-Based Compensation - Stock Based Compensation Table (Details) (USD $)	3 Months Ended		12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,000,000	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period, Net	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,000,000	'	1,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,779,983	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Period Increase (Decrease)	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	-44,920	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Other Increases (Decreases) in Period	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	-32,647	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,702,416	'	1,779,983
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	761,103	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$24.60	'	$24.76
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$0	'	'
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$12.05	'	'
Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price	$0	'	'
Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price	$50.64	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$23.91	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Grant Date Fair Value	$11.52	'	$11.44
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Excrecises in Period, Weighted Average Grant Date Fair Value	$6.22	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeited in Period, Weighted Average Grant Date Fair Value	$0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expired in Period, Weighted Average Grant Date Fair Value	$14.27	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Excercisable, Weighted Average Grant Date Fair Value	$9.75	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	'4 years 9 months 22 days	'	'4 years 10 months 13 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	'1 year 8 months 23 days	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$3.30	'	$4.80
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	3.3	'	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options	9.5	'	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'6 years 3 months 22 days	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$0.60	$0.50	'

StockBased_Compensation_Restri

Stock-Based Compensation - Restricted Stock Plan (Details)	3 Months Ended	12 Months Ended
Stock-Based Compensation - Restricted Stock Plan (Details)	Dec. 31, 2013	Sep. 30, 2013
Stock-Based Compensation [Abstract]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	1,138,250	1,154,862

StockBased_Compensation_Restri1

Stock-Based Compensation - Restricted Stock Plan Table (Details) (USD $)	3 Months Ended	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	1,138,250	1,154,862
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Period Increase (Decrease)	-47,423	'
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Forfeitures	30,811	'
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	1,138,250	1,154,862
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	363,638	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	47,423	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	-102,581	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	-54,447	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	254,033	363,638
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$20.53	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$20.35	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$19.76	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$21.68	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$20.55	$20.53
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms	'2 years 4 days	'1 year 8 months 27 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms	'2 years 4 days	'1 year 8 months 27 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Intrinsic Value	$7,400,000	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Intrinsic Value	$4,700,000	$7,400,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$4.10	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition - Restricted Stock	'2 years 15 days	'

Other_Expenses_Other_Expenses_

Other Expenses - Other Expenses Breakout (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Component of Operating Other Cost and Expense [Line Items]	'	'
Other Cost and Expense, Operating	$4.70	$6.60
Contingent Consideration [Member]	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'
Other Cost and Expense, Operating	0.2	0.7
Insurance Expense [Member]	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'
Other Cost and Expense, Operating	0.5	0.5
Advertising, meetings and conferences [Member]	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'
Other Cost and Expense, Operating	0.4	0.4
Non-trading hardware and software maintenance and software licensing [Member]	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'
Other Cost and Expense, Operating	0.7	0.6
Office supplies and printing [Member]	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'
Other Cost and Expense, Operating	0.3	0.3
Other clearing related expenses [Member]	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'
Other Cost and Expense, Operating	0.4	0.4
Other non-income taxes [Member]	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'
Other Cost and Expense, Operating	1	1.1
Other [Member]	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'
Other Cost and Expense, Operating	$1.20	$2.60

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Taxes [Abstract]	'	'	'	'	'
Deferred Tax Assets, Valuation Allowance	$2.30	'	$2.30	'	'
Valuation Allowance, Deferred Tax Asset, Change in Amount	'	'	1.8	'	'
Taxable Income (Loss) from Continuing Operations before Income Taxes, Domestic	'	'	-22.2	-21.2	22.7
Deferred Tax Liability Not Recognized, Cumulative Amount of Temporary Difference	4.3	'	'	'	'
Deferred Tax Liabilities, Unrealized Gains on Trading Securities	1.3	'	'	'	'
Income Tax Expense (Benefit)	$1.50	$5.50	'	'	'
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate	38.00%	29.00%	'	'	'

Acquisitions_and_Dispositions_1

Acquisitions and Dispositions - Dispositions (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	$4	$18.80
INTL Commodities - Physical Base Metals [Domain]	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	$0.10	$4.70

Segment_Analysis_Reportable_Se

Segment Analysis - Reportable Segments (Details)	3 Months Ended
Segment Analysis - Reportable Segments (Details)	Dec. 31, 2013
Segment Analysis [Abstract]	'
Number of different types of foreign currencies	130

Segment_Analysis_Details

Segment Analysis (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013
Segment Reporting Information [Line Items]	'	'	'
Revenues	$7,938	$12,552.80	'
Gross Profit	113.4	125.7	'
Net Contribution	57.7	64.2	'
Net Segment Income	29.5	34	'
Costs not allocated	25.5	15.2	'
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	4	18.8	'
Assets	2,743.90	'	2,848
Commodity and Risk Management [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	7,766.90	12,453.10	'
Gross Profit	48.5	60.7	'
Net Contribution	29.2	40.5	'
Net Segment Income	13.1	22.7	'
Assets	1,057.20	'	1,105.10
Foreign Exchange Segment [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	18.3	16.2	'
Gross Profit	18.3	16.2	'
Net Contribution	12.1	10.4	'
Net Segment Income	8.1	7.1	'
Assets	126.8	'	145
Securities Segment [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	17.6	12.9	'
Gross Profit	17.6	12.9	'
Net Contribution	8.6	6.9	'
Net Segment Income	4.3	3.2	'
Assets	226.6	'	198.5
Clearing and Execution Services Segment [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	23.8	22.4	'
Gross Profit	23.8	22.4	'
Net Contribution	3.7	3.6	'
Net Segment Income	1.1	-0.9	'
Assets	1,164.80	'	1,246.40
Other Segment [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	111.8	39.5	'
Gross Profit	5.6	4.8	'
Net Contribution	4.1	2.8	'
Net Segment Income	2.9	1.9	'
Assets	54.7	'	37.3
Corporate [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	-0.4	8.7	'
Gross Profit	-0.4	8.7	'
Assets	$113.80	'	$115.70