StoneX (SNEX) 10-K 15 Jan 14 2013 FY Annual report Financial data

DEI_Document

DEI Document (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Jan. 13, 2014	Mar. 31, 2013
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-K	'	'
Document Period End Date	30-Sep-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Amendment Flag	'false	'	'
Entity Common Stock, Shares Outstanding	'	19,188,599	'
Entity Well-known Seasoned Issuer	'No	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Public Float	'	'	$238.40

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Cash and cash equivalents	$156.10	$236.30
Cash, securities and other assets segregated under federal and other regulations (including $107.6 and $72.8 at fair value at September 30, 2013 and September 30, 2012 respectively)	449.4	357.5
Deposits with and receivables from:	'	'
Exchange-clearing organizations (including $1,371.7 and $1,510.0 at fair value at September 30, 2013 and September 30, 2012, respectively)	1,576.60	1,619.80
Broker-dealers, clearing organizations and counterparties (including $(13.1) and $(0.7) at fair value at September 30, 2013 and September 30, 2012, respectively)	168.3	116.8
Receivables from customers, net	93.3	68.9
Notes receivable, net	37.4	104
Income taxes receivable	15.5	15.5
Financial instruments, owned, at fair value	158.5	171.7
Physical commodities inventory	59	131.6
Deferred income taxes, net	25.5	21.9
Property and equipment, net	17.5	18.9
Goodwill and intangible assets, net	59.1	55.8
Other assets	31.8	34.3
Total assets	2,848	2,953
Liabilities:	'	'
Accounts payable and other accrued liabilities (including $9.6 and $14.8 at fair value at September 30, 2013 and September 30, 2012)	114	127
Payables to:	'	'
Customers	2,091.80	2,072.30
Broker-dealers, clearing organizations and counterparties	17	39.4
Lenders under loans	61	218.2
Senior unsecured notes	45.5	0
Income taxes payable	3.4	5.5
Financial instruments sold, not yet purchased, at fair value	179.9	175.4
Deferred income taxes	0	2
Total liabilities	2,512.60	2,639.80
Commitments and contingencies (Note 11)	'	'
INTL FCStone Inc. stockholders’ equity:	'	'
Preferred stock, $.01 par value. Authorized 1,000,000 shares; no shares issued or outstanding	0	0
Common stock, $.01 par value. Authorized 30,000,000 shares; 19,638,330 issued and 19,209,157 outstanding at September 30, 2013 and 19,214,219 issued and 18,984,951 outstanding at September 30, 2012	0.2	0.2
Common stock in treasury, at cost - 429,173 shares at September 30, 2013 and 229,064 shares at September 30, 2012	-7.8	-4.1
Additional paid-in capital	224	213.2
Retained earnings	125.4	106.1
Accumulated other comprehensive loss, net	-6.4	-2.2
Total stockholders' equity	335.4	313.2
Total liabilities and equity	$2,848	$2,953

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, except Share data, unless otherwise specified
Assets [Abstract]	'	'
Securities and other assets segregated, fair value	$107.60	$72.80
Dep and rec -exch clear org - fair value	1,371.70	1,510
Dep and rec -b/d- fair value	-13.1	-0.7
Accounts pay and other accrued - fair value	$9.60	$14.80
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	19,638,330	19,214,219
Common stock - outstanding	19,209,157	18,984,951
Treasury Stock - Shares	429,173	229,064

Consolidated_Income_Statements

Consolidated Income Statements (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Revenues:	'	'	'
Sales of physical commodities	$43,283.70	$67,514.70	$72,521.20
Trading gains, net	265	244.9	201.6
Commission and clearing fees	173.3	161	134.5
Consulting and management fees	35.1	27.9	22.7
Interest income	10.3	10.3	10.3
Other Income	0.9	0.5	1
Total revenues	43,768.30	67,959.30	72,891.30
Cost of sales of physical commodities	43,289.90	67,505.10	72,472.20
Operating revenues	478.4	454.2	419.1
Clearing and related expenses	110.1	105.4	75.6
Introducing broker commissions	40.5	31	24
Interest expense	12.5	11.6	11.3
Net operating revenues	315.3	306.2	308.2
Compensation and other expenses:	'	'	'
Compensation and benefits	201.6	202.4	176.6
Communication and data services	23.3	22.6	15.5
Occupancy and equipment rental	12	11	8.9
Professional fees	13.1	12.9	10.6
Travel and business development	10.7	11.2	8.9
Depreciation and amortization	8	7.2	4.7
Bad debts and impairments	0.8	1.5	6.2
Other	23.2	21.6	21.4
Total compensation and other expenses	292.7	290.4	252.8
Income from continuing operations, before tax	22.6	15.8	55.4
Income tax expense	3.3	3.1	20.9
Net income from continuing operations	19.3	12.7	34.5
Income from discontinued operations, net of tax	0	0	0.2
Net income	19.3	12.7	34.7
Add: Net loss attributable to noncontrolling interests	0	0.1	0.1
Net income attributable to INTL FCStone Inc. common stockholders	19.3	12.8	34.8
Basic earnings per share:	'	'	'
Income from continuing operations attributable to INTL FCStone Inc. common stockholders	$1.01	$0.67	$1.92
Income from discontinued operations attributable to INTL FCStone Inc. common stockholders	$0	$0	$0.01
Net income attributable to INTL FCStone Inc. common stockholders	$1.01	$0.67	$1.93
Diluted earnings per share:	'	'	'
Income from continuing operations attributable to INTL FCStone Inc. common stockholders	$0.97	$0.64	$1.82
Income from discontinued operations attributable to INTL FCStone Inc. common stockholders	$0	$0	$0.01
Net income attributable to INTL FCStone Inc. common stockholders	$0.97	$0.64	$1.83
Weighted-average number of common shares outstanding:	'	'	'
Basic	18,443,233	18,282,939	17,618,085
Diluted	19,068,497	19,156,899	18,567,454
Amounts attributable to INTL FCStone Inc. common stockholders:	'	'	'
Income from continuing operations, net of tax	19.3	12.8	34.6
Income from discontinued operations, net of tax	0	0	0.2
Net income attributable to INTL FCStone Inc. common stockholders	$19.30	$12.80	$34.80

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income Statement (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Statement of Other Comprehensive Income [Abstract]	'	'	'
Net income	$19.30	$12.70	$34.70
Foreign currency translation adjustment	-1.8	-1.1	-0.4
Net unrealized gain on derivative instruments	0	0	1
Pension liabilities adjustment	3.4	-1.6	-2.9
Net unrealized gain or loss on available-for-sale securities	0.6	6.5	-0.6
Foreign currency translation adjustment (included in other income)	-0.1	0	0
Realized gain on available-for-sale securities (included in trading gains, net)	-8.3	0	0
Income tax expense from reclassification adjustments (included in income tax expense)	2	0	0
Reclassification adjustment for gains included in net income	-6.4	0	0
Other comprehensive (loss) income	-4.2	3.8	-2.9
Comprehensive income	$15.10	$16.50	$31.80

Consolidated_Cash_Flows_Statem

Consolidated Cash Flows Statements (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:	'	'	'
Net income	$19.30	$12.70	$34.70
Adjustments to reconcile net income to net cash provided by (used in) operating activities:	'	'	'
Depreciation and amortization	8	7.2	4.7
Provision for bad debts and impairments	0.8	1.7	6.2
Deferred income taxes	-7.8	-0.3	1.8
Amortization of debt issuance costs and debt discount	1.2	1.7	1.6
Convertible debt interest settled in company stock upon conversion	0	0	0.2
Amortization of stock-based compensation expense	9.3	5.9	2.3
Loss on sale of property and equipment	0.4	0	0
Gain on disposition of affiliates	-0.4	0	0
Gain on sale of exchange memberships and common stock	-9.1	0	0
Gain on acquisition of INTL Provident	0	0	-0.4
Changes in operating assets and liabilities, net:	'	'	'
Cash, securities and other assets segregated under federal and other regulations	-95.1	-199.9	-104.1
Deposits and receivables from exchange-clearing organizations	42.3	-97.7	-586
Deposits and receivables from broker-dealers, clearing organizations, and counterparties	-53.4	46.2	51.2
Receivable from customers, net	-23.7	46.4	-39.1
Notes receivable, net	66.6	-77.9	2.9
Income taxes receivable	-0.2	-3.1	0.6
Financial instruments owned, at fair value	3.1	58.3	280.7
Physical commodities inventory	72.7	29	-35.6
Other assets	4.3	-1.6	-12.1
Accounts payable and other accrued liabilities	-0.2	10.6	30.8
Payable to customers	24	248	366.2
Payable to broker-dealers, clearing organizations and counterparties	-22.3	35.9	-0.5
Income taxes payable	0.5	0.3	0
Financial instruments sold, not yet purchased, at fair value	4.6	-215.5	202.9
Net cash provided by (used in) operating activities	44.9	-92.1	209
Cash flows from investing activities:	'	'	'
Deconsolidation of affiliates	0	0.4	0
Disposition of affiliates	-0.2	0	0
Cash paid for other acquisitions, net	0	-11.7	-9.3
Purchase of exchange memberships and common stock	-0.3	0	-3.4
Sale of exchange memberships and common stock	10.1	0	1.3
Purchase of property and equipment	-4.9	-8.7	-10.1
Net cash provided by (used in) investing activities	5.1	-20	-21.5
Cash flows from financing activities:	'	'	'
Net change in payable to lenders under loans	-157.2	140.8	-37.5
Payments related to earn-outs on acquisitions	-12	-9.6	-9.4
Proceeds from issuance of senior unsecured notes	45.5	0	0
Repayment of subordinated debt	0	0	-0.5
Share repurchase	-3.9	-4	0
Debt issuance costs	-3.7	-0.3	-2.4
Exercise of stock options	1.5	1.9	1.4
Income tax benefit on stock options and awards	0.1	0.2	0
Net cash (used in) provided by financing activities	-129.7	129	-48.4
Effect of exchange rates on cash and cash equivalents	-0.5	-1.2	-0.4
Net increase (decrease) in cash and cash equivalents	-80.2	15.7	138.7
Cash and cash equivalents at beginning of period	236.3	220.6	81.9
Cash and cash equivalents at end of period	156.1	236.3	220.6
Supplemental disclosure of cash flow information:	'	'	'
Cash paid for interest	8.9	7.9	9.5
Income taxes paid (received), net of cash refunds	10.2	6.1	17.6
Supplemental disclosure of non-cash investing and financing activities:	'	'	'
Conversion of subordinated notes to common stock, net	0	0	16.7
Identified intangible assets and goodwill on acquisitions	5.6	1.8	4.9
Additional consideration payable related to acquisitions	$8.20	$2.10	$5.40

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders’ Equity (USD $)

Total

Common Stock [Member]

Treasury Stock [Member]

Additional Paid-in Capital [Member]

Retained Earnings [Member]

Accumulated Other Comprehensive Income [Member]

Noncontrolling Interest [Member]

As Reported [Member]

As Reported [Member]

As Reported [Member]

As Reported [Member]

As Reported [Member]

As Reported [Member]

As Reported [Member]

Cumulative Prior Period Adjustments [Member]

Cumulative Prior Period Adjustments [Member]

As Restated [Member]

As Restated [Member]

As Restated [Member]

As Restated [Member]

As Restated [Member]

As Restated [Member]

As Restated [Member]

In Millions, unless otherwise specified

Common Stock [Member]

Treasury Stock [Member]

Additional Paid-in Capital [Member]

Retained Earnings [Member]

Accumulated Other Comprehensive Income [Member]

Noncontrolling Interest [Member]

Retained Earnings [Member]

Common Stock [Member]

Treasury Stock [Member]

Additional Paid-in Capital [Member]

Retained Earnings [Member]

Accumulated Other Comprehensive Income [Member]

Noncontrolling Interest [Member]

Balances at beginning of period at Sep. 30, 2010

'

'

'

'

'

'

'

$242.90

$0.20

($0.10)

$184.60

$59.70

($3.10)

$1.60

($1.20)

($1.20)

$241.70

$0.20

($0.10)

$184.60

$58.50

($3.10)

$1.60

Components of comprehensive income

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net income

34.7

'

'

'

34.8

'

-0.1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other comprehensive (loss) income

-2.9

'

'

'

'

-2.9

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Redemption of fund units

-0.2

'

'

'

'

'

-0.2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Excercise of stock options

1.4

'

'

1.4

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock-based Compensation

2.3

'

'

2.3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Convertible note conversions

16.9

'

'

16.9

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balances at end of period at Sep. 30, 2011

293.9

0.2

-0.1

205.2

93.3

-6

1.3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Components of comprehensive income

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net income

12.7

'

'

'

12.8

'

-0.1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other comprehensive (loss) income

3.8

'

'

'

'

3.8

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Excercise of stock options

2.1

'

'

2.1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock-based Compensation

5.9

'

'

5.9

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Repurchase of stock

-4

'

-4

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Disposition or de-consolidation

-1.2

'

'

'

'

'

-1.2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balances at end of period at Sep. 30, 2012

313.2

0.2

-4.1

213.2

106.1

-2.2

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Components of comprehensive income

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net income

19.3

'

'

'

19.3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other comprehensive (loss) income

-4.2

'

'

'

'

-4.2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Excercise of stock options

1.5

'

'

1.5

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock-based Compensation

9.3

'

'

9.3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Repurchase of stock

-3.9

'

-3.7

-0.2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock held in escrow for business combination

0.2

'

'

0.2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balances at end of period at Sep. 30, 2013

$335.40

$0.20

($7.80)

$224

$125.40

($6.40)

$0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Condensed_Parent_Only_Financia

Condensed Parent Only Financial Statements [Schedule] Balance Sheet (Parentheticals) (USD $)	Sep. 30, 2013	Sep. 30, 2012
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'	'
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	19,638,330	19,214,219
Common stock - outstanding	19,209,157	18,984,951
Treasury Stock - Shares	429,173	229,064

Description_of_Business_and_Si

Description of Business and Significant Accounting Policies Description of Business and Significant Accounting Policies (Notes)	12 Months Ended
	Sep. 30, 2013
Organization, Consolidation, Presentation of Financial Statements and Accounting Policies [Abstract]	'
Business Description and Accounting Policies [Text Block]	'
	Description of Business and Significant Accounting Policies
	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; structured over-the-counter (“OTC”) products in a wide range of commodities; physical trading and hedging of precious and base 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
	The accompanying 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.
	Unless otherwise stated herein, all references to fiscal 2013, fiscal 2012, and fiscal 2011 refer to the Company’s fiscal years ended September 30.
	Reclassifications
	Certain amounts previously reported 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 net income or consolidated assets and liabilities.
	Use of Estimates
	The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“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. These estimates are based on management’s best knowledge of current events and actions the Company may undertake in the future. The Company reviews all significant estimates affecting the financial statements on a recurring basis and records the effect of any necessary adjustments prior to their issuance. Although these and other estimates and assumptions are based on the best available information, actual results could be materially different from these estimates.
	Foreign Currency Translation
	Assets and liabilities recorded in foreign currencies are translated at the exchange rates prevailing on the balance sheet date. Revenue and expenses are translated at average rates of exchange prevailing during the period. Gains or losses on translation of the financial statements of a non-United States (“U.S.”) operation, when the functional currency is other than the U.S. dollar, are recorded in other comprehensive income (“OCI”), net of tax, a component of stockholders’ equity. Foreign currency remeasurement gains or losses on transactions in nonfunctional currencies are included in ‘trading gains, net’ in the consolidated income statements.
	Cash and Cash Equivalents
	The Company considers cash held at banks and all highly liquid investments, including certificates of deposit, which may be withdrawn at any time at the discretion of the Company without penalty, to be cash and cash equivalents. Cash and cash equivalents consist of cash, foreign currency, money market funds and certificates of deposit not deposited with or pledged to exchange-clearing organizations, broker-dealers, clearing organizations or counterparties. The money market funds are valued at period-end at the net asset value provided by the fund’s administrator, which approximates fair value. Certificates of deposit are stated at cost plus accrued interest, which approximates fair value. The Company has an investment policy, which limits the maximum amount placed in any one fund and with any one institution in order to reduce credit risk. The Company does not believe that it is exposed to significant risk on cash and cash equivalents.
	Cash, Securities and Other Assets Segregated under Federal and other Regulations
	Pursuant to requirements of the Commodity Exchange Act in the U.S. and similarly in the United Kingdom (“UK”), pursuant to the Markets in Financial Instruments Implementing Directive 2006/73/EC underpinning the Client Asset or ‘CASS’ rules in the Financial Services Authority (“FSA”) handbook, funds deposited by customers relating to futures and options-on-futures contracts in regulated commodities must be carried in separate accounts which are designated as segregated customer accounts. The deposits in segregated customer accounts are not commingled with the funds of the Company. Under the FSA’s rules, certain categories of clients may choose to opt-out of segregation. As of September 30, 2013 and 2012, cash, securities and other assets segregated under federal and other regulations consisted of cash held at banks and money market funds of approximately $416.8 million and $284.7 million, respectively, U.S. government securities and federal agency obligations of approximately $19.5 million and $50.5 million, respectively, and commodities warehouse receipts of approximately $13.1 million and $22.3 million, respectively (see fair value measurements discussion in Note 4).
	Securities purchased under agreements to resell
	The Company has an overnight sweep reverse repurchase agreement program to allow the Company to enter into secured overnight investments (reverse repurchase agreements or reverse repos), which generally provides a higher investment yield than a regular operating account. The reverse repurchase agreements are recorded at amounts at which the securities were initially acquired. It is the policy of the Company to take possession of the securities purchased under agreements to resell. The Company receives U.S. Treasury securities as collateral for the overnight agreements. The securities received are recorded at no more than the lesser of the current fair value of the securities or the net amount to be realized by the Company upon resale of the securities. The maturity of the reverse repurchase agreements is typically one day, at which point the securities are sold and the proceeds are returned to the Company, plus any accrued interest. There were no agreements to resell securities as of September 30, 2013 and 2012.
	Deposits and Receivables from Exchange-Clearing Organizations, Broker-dealers, Clearing Organizations and Counterparties, and Payables to Broker-dealers, Clearing Organizations and Counterparties
	As required by the regulations of the U.S. Commodity Futures Trading Commission (“CFTC”) and the Markets in Financial Instruments Implementing Directive 2006/73/EC underpinning the CASS rules in the FSA handbook, customer funds received to margin, guarantee, and/or secure commodity futures transactions are segregated and accounted for separately from the general assets of the Company. Under the FSA’s rules, certain categories of clients may choose to opt-out of segregation. Deposits with exchange-clearing organizations, broker-dealers and counterparties pertain primarily to deposits made to satisfy margin requirements on customer and proprietary open futures and options-on-futures positions and to satisfy the requirements set by clearing exchanges for clearing membership. The Company also pledges margin deposit with various counterparties for OTC derivative contracts, and these deposits are also included in deposits and receivables from broker-dealers and counterparties. Deposits with and receivables from exchange-clearing organizations and broker-dealers and counterparties are reported gross, except where a right of offset exists. As of September 30, 2013 and 2012, the Company had cash and cash equivalents on deposit with or pledged to exchange-clearing organizations, broker-dealers and counterparties of $1.0 billion and $0.4 billion, respectively.
	These balances also include securities pledged by the Company on behalf of customers and customer-owned securities that are pledged. It is the Company’s practice to include customer owned securities on its consolidated balance sheets, as the rights to those securities have been transferred to the Company under the terms of the futures trading agreement. Securities pledged include U.S. Treasury bills and instruments backed by U.S. government sponsored entities and government-sponsored enterprise backed mortgage-backed securities (“mortgage-backed securities”). The securities that are not customer-owned are adjusted to fair value with associated changes in unrealized gains or losses recorded in OCI, net of tax, until realized, a component of stockholders’ equity. For customer owned securities, the change in fair value is offset against the payable to customers with no impact recognized on the consolidated income statements.
	The securities, primarily U.S. Government obligations and mortgage-backed securities, held by FCStone LLC (“FCStone”), a subsidiary of INTL, as collateral or as margin have been deposited with exchange-clearing organizations, broker-dealers or other counterparties. The fair value of these securities was approximately $0.6 billion and $1.3 billion as of September 30, 2013 and 2012, respectively.
	Management has considered guidance required by the Transfers and Servicing Topic of the ASC as it relates to securities pledged by customers to margin their accounts. Based on a review of the agreements with the customer, management believes a legal basis exists to support that the transferor surrenders control over those assets if all of the following three conditions are met: (a) the transferred assets have been isolated from the transferor—put presumptively beyond the reach of the transferor and its creditors, even in bankruptcy or other receivership, (b) each transferee has the right to pledge or exchange the assets (or beneficial interests) it received, and no condition both constrains the transferee (or holder) from taking advantage of its right to pledge or exchange and provides more than a trivial benefit to the transferor and (c) the transferor does not maintain effective control over the transferred assets through either (1) an agreement that both entitles and obligates the transferor to repurchase or redeem them before their maturity or (2) the ability to unilaterally cause the holder to return specific assets, other than through a cleanup call. Under this guidance, the Company reflects the customer collateral assets and corresponding liabilities in the Company’s consolidated balance sheets as of September 30, 2013 and 2012.
	In addition to margin, deposits with exchange-clearing organizations include guaranty deposits. The guaranty deposits are held by the clearing organization for use in potential default situations by one or more members of the clearing organization. The guaranty deposits may be applied to the Company’s obligations to the clearing organization, or to the clearing organization’s obligations to other clearing members or third parties.
	The Company maintains customer omnibus and proprietary accounts with other counterparties, and the equity balances in those accounts along with any margin cash or securities deposited with the carrying broker are included in deposits and receivables from broker-dealers and counterparties.
	Receivables from and payables to exchange-clearing organizations are also comprised of amounts due from or due to exchange-clearing organizations for daily variation settlements on open futures and options-on-futures positions. The variation settlements due from or due to exchange-clearing organizations are paid in cash on the following business day.
	Deposits and receivables with exchange-clearing organizations also includes the unrealized gains and losses associated with the customers’ options-on-futures contracts. See discussion in the Financial Instruments and Derivatives section below for additional information on the treatment of derivative contracts. For customer owned derivative contracts, the fair value is offset against the payable to customers with no impact recognized on the consolidated income statements.
	Receivable from and Payable to Customers
	Receivable from customers, net of the allowance for doubtful accounts, include the total of net deficits in individual exchange-traded and OTC trading accounts carried by the Company. Customer deficits arise from realized and unrealized trading losses on futures, options-on-futures, swaps and forwards and amounts due on cash and margin transactions. Customer deficit accounts are reported gross of customer accounts that contain net credit or positive balances, except where a right of offset exists. Net deficits in individual exchange-traded and OTC trading accounts include both secured and unsecured deficit balances due from customers as of the balance sheet date. Secured deficit amounts are backed by U.S. Treasury bills and notes and commodity warehouse receipts. These U.S Treasury bills and notes and commodity warehouse receipts are not netted against the secured deficit amounts, as the conditions for right of setoff have not been met.
	Payable to customers represent the total of customer accounts with credit or positive balances. Customer accounts are used primarily in connection with commodity transactions and include gains and losses on open commodity trades as well as securities and other deposits made as required by the Company or the exchange-clearing organizations or counterparties. Customer accounts with credit or positive balances are reported gross of customer deficit accounts, except where a right of offset exists.
	For regulatory purposes, certain customers, which would include persons who are affiliated with the Company or are principals, such as an officer or director, and any person who is materially involved in the management of the Company, are identified as noncustomers. A noncustomer account may not be carried as a customer account due to an affiliation with the Company. In a liquidation event, amounts owed to noncustomers are paid in the same priority as amounts owed to general creditors of the Company. These accounts are also referred to as proprietary accounts. The amounts related to noncustomer accounts are included in ‘payable to customers’ on the consolidated balance sheets.
	The future collectability of the receivable from customers can be impacted by the Company’s collection efforts, the financial stability of its customers, and the general economic climate in which it operates. The Company evaluates accounts that it believes may become uncollectible on a specific identification basis, through reviewing daily margin deficit reports, the historical daily aging of the receivables, and by monitoring the financial strength of its customers. The Company may unilaterally close customer trading positions in certain circumstances. In addition, to evaluate customer margining and collateral requirements, customer positions are stress tested regularly and monitored for excessive concentration levels relative to the overall market size.
	The Company generally charges off an outstanding receivable balance when all economically sensible means of recovery have been exhausted. That determination considers information such as the occurrence of significant changes in the customer’s financial position such that the customer can no longer pay the obligation, or that the proceeds from collateral will not be sufficient to pay the balance.
	Notes Receivable
	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 Company may sell the insured portion of the notes through non-recourse participation agreements with other third parties. See discussion of notes receivable related to commodity repurchase agreements below.
	Accrual of commodity financing income on any note is discontinued when, in the opinion of management, there is reasonable doubt as to the timely collectability of interest or principal. Nonaccrual notes are returned to an accrual status when, in the opinion of management, the financial position of the borrower indicates there is no longer any reasonable doubt as to the timely payment of principal and interest. The Company records a charge against earnings for notes receivable losses when management believes that collectability of the principal is unlikely.
	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 costing method. Cost includes finished commodity or raw material and processing costs related to the purchase and processing of inventories.
	Property and Equipment
	Property and equipment is stated at cost, net of accumulated depreciation and amortization and depreciated using the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized on a straight-line basis over the estimated useful life of the improvement or the term of the lease, whichever is shorter. Certain costs of software developed or obtained for internal use are capitalized and amortized over the estimated useful life of the software. Expenditures for maintenance, repairs, and minor replacements are charged against earnings, as incurred. Expenditures that increase the value or productive capacity of assets are capitalized. When property and equipment are retired, sold, or otherwise disposed of, the asset’s carrying amount and related accumulated depreciation are removed from the accounts and any gain or loss is included in earnings.
	Goodwill and Identifiable Intangible Assets
	Goodwill is the cost of acquired companies in excess of the fair value of identifiable net assets at acquisition date. In accordance with the Intangibles – Goodwill and Other Topic of the ASC, goodwill is tested for impairment on an annual basis at the fiscal year-end, and between annual tests if indicators of potential impairment exist, using a fair-value-based approach. No impairment of goodwill has been identified during any of the periods presented.
	Identifiable intangible assets subject to amortization are amortized using the straight-line method over their estimated period of benefit, ranging from two to twenty years. Identifiable intangible assets are tested for impairment whenever events or changes in circumstances suggest that an asset’s or asset group’s carrying value may not be fully recoverable in accordance with the Intangibles – Goodwill and Other Topic of the ASC. Residual value is presumed to be zero. Identifiable intangible assets not subject to amortization are reviewed at each reporting period to reevaluate if the intangible asset’s useful life remains indefinite. Additionally, intangible assets not subject to amortization are tested annually for impairment at the fiscal year-end, and between annual tests if indicators of potential impairment exist, using a fair-value-based approach. See Note 10 for discussion of impairments of intangible assets that have been identified during the fiscal years ended September 30, 2013 and 2012.
	Financial Instruments and Derivatives
	Financial instruments owned and sold, not yet purchased, at fair value consist of financial instruments carried at fair value or amounts that approximate fair value, with related unrealized changes in gains or losses recognized in earnings, except for securities classified as available-for-sale. The fair value of a financial instrument is the amount at which the instrument could be exchanged in a current transaction between willing parties, other than in a forced or liquidation sale.
	The Company accounts for its securities pledged on behalf of customers and proprietary securities in accordance with the Investments - Debt and Equity Securities Topic in the ASC. In accordance with this guidance, the Company determines the appropriate classification of its investments as trading, available-for-sale, or held-to-maturity at the time of purchase and reevaluates the designation as of each reporting period.
	The Company has classified certain U.S. government obligations, corporate debt securities and exchange firm common stock not pledged for clearing purposes as available-for-sale, which are carried at fair value based on observable or quoted market prices and associated unrealized gains or losses are recorded as a component of OCI, net of tax, until realized, unless an unrealized loss is determined to be other than temporary, in which case such loss is charged to earnings. The Company classifies those securities as available-for-sale because it would consider selling them prior to maturity to meet liquidity needs or as part of the Company’s risk management program.
	The Company computes the cost of its securities on a specific identification basis. Such cost includes the direct costs to acquire securities, adjusted for the amortization of any discount or premium. The amortized cost of securities is computed under the effective-interest method and is included in interest income. Realized gains and losses, declines in value judged to be other than temporary and interest on available-for-sale securities are included in earnings.
	Investment in managed funds, at fair value represents investments in funds managed by the Company’s fund managers. The investments are valued at period-end at the net asset value provided by the fund’s administrator.
	Commodities warehouse receipts are valued at the cash price, or the nearby futures prices in the absence of a cash price, for the commodity based on published market quotes. For commodities warehouse receipts, the change in fair value is offset against the payable to customers with no impact on the consolidated income statements.
	The Company utilizes derivative instruments to manage exposures to foreign currency, commodity price and interest rate risks for the Company and its customers. The Company’s objectives for holding derivatives include reducing, eliminating, and efficiently managing the economic impact of these exposures as effectively as possible. Derivative instruments are recognized as either assets or liabilities and are measured at fair value. The accounting for changes in the fair value of a derivative depends on the intended use of the derivative and the resulting designation. For a derivative instrument designated as a cash flow hedge, the effective portion of the derivative’s gain or loss is initially recorded in OCI, net of tax, and is subsequently recognized in earnings when the hedged exposure affects earnings. The ineffective portion of the gain or loss is recognized in earnings. Gains and losses from changes in fair values of derivatives that are not designated as cash flow hedges for accounting purposes are recognized in earnings.
	The Company’s derivative contracts consist of exchange-traded and OTC derivatives. Fair values of exchange-traded derivatives are generally determined from quoted market prices. OTC derivatives are valued using valuation models. The valuation models used to derive the fair values of OTC derivatives require inputs including contractual terms, market prices, yield curves and measurements of volatility. The Company uses similar models to value similar instruments. Where possible, the Company verifies the values produced by pricing models by comparing them to market transactions. Inputs may involve judgment where market prices are not readily available. The Company does not elect hedge accounting under the Derivatives and Hedging Topic of the ASC in accounting for derivatives used as economic hedges on its commodities.
	The Company provides clearing and execution of exchange-traded futures and options-on-futures for middle-market intermediaries, end-users, producers of commodities and the institutional and professional trader market segments. The Company has a subsidiary that is a registered futures commission merchant (“FCM”), clearing on various exchanges. The primary sources of revenues for the Company’s FCM are commissions and clearing fees derived from executing and clearing orders for commodity futures contracts and options-on-futures on behalf of its customers.
	The Company also brokers foreign exchange forwards, options and cash, or spot, transactions between customers and external counterparties. A portion of the contracts are arranged on an offsetting basis, limiting the Company’s risk to performance of the two offsetting parties. The offsetting nature of the contracts eliminates the effects of market fluctuations on the Company’s operating results. Due to the Company’s role as a principal participating in both sides of these contracts, the amounts are presented gross on the consolidated balance sheets at their respective fair values, net of offsetting assets and liabilities.
	In addition, the Company engages in speculative trading and holds proprietary positions in futures, options, swaps and forward derivatives, including corn, wheat, soybeans, sugar and foreign currency contracts. Since some of the derivatives held or sold by the Company are for speculative trading purposes, these derivative instruments are not designated as hedging instruments and accordingly, the changes in fair value during the period are recorded in the consolidated income statements as a component of ‘trading gains, net’ (see Note 5).
	The Company also holds proprietary positions in its foreign exchange line of business. On a limited basis, the Company’s foreign exchange trade desk will accept a customer transaction and will offset that transaction with a similar but not identical position with a counterparty. These unmatched transactions are intended to be short-term in nature and are often conducted to facilitate the most effective transaction for the Company’s customer. These spot and forward contracts are accounted for as free-standing derivatives and reported in the consolidated balance sheets at their fair values. The Company does not seek hedge accounting treatment for these derivatives, and accordingly, the changes in fair value during the period are recorded in the consolidated income statements in ‘trading gains, net’ (see Note 5). In applying the guidance in the Balance Sheet-Offsetting Topic of the ASC, the Company’s accounting policy is such that open contracts with the same customer are netted at the account level, in accordance with netting arrangements in place with each party, as applicable and rights to reclaim cash collateral or obligations to return cash collateral are netted against fair value amounts recognized for derivative instruments with the same customer in accordance with the master netting arrangements in place with each customer.
	The Company may lease commodities to or from customers or counterparties, or advance commodities to customers on an unpriced basis, receiving payment when they become priced. These are valued at fair value utilizing the fair value option based on guidance in the Financial Instruments Topic of the ASC. As permitted by the fair value option election, the entire instrument is recorded at fair value in the consolidated balance sheets as a component of ‘financial instruments owned and sold, not yet purchased’. Due to the short term nature of the instruments, the balance of the agreements is not materially different than the recorded fair value. The corresponding change in fair value of the instrument is recognized in the consolidated income statements as a component of ‘trading gains, net’ for the fiscal years ended 2013, 2012 and 2011. The Company does elect to value all of their commodities lease agreements at fair value using the fair value option. See fair value measurements in Note 4.
	Exchange Memberships and Stock
	The Company is required to hold certain exchange membership seats and exchange firm common stock and pledge them for clearing purposes, in order to provide the Company the right to process trades directly with the various exchanges. Exchange memberships include seats on the Chicago Board of Trade (“CBOT”), the Minneapolis Grain Exchange, the New York Mercantile Exchange (“NYMEX”), the Commodity Exchange, Inc. (“COMEX”) Division of the New York Mercantile Exchange, Mercado de Valores de Buenos Aires S.A. (“MERVAL”), the Chicago Mercantile Exchange (“CME”) Growth and Emerging Markets, InterContinental Exchange, Inc. (“ICE”) Futures US, ICE Europe Ltd and London Metal Exchange (“LME”). Exchange firm common stock include shares of CME Group, Inc., ICE and LME. In December 2012, the CME completed its acquisition of the Board of Trade of Kansas City, Missouri, Inc. (“KCBT”). The Company received proceeds of $1.5 million and recognized a gain of $0.9 million before taxes, in connection with its class A shares of the KCBT held as of September 30, 2012, during the fiscal year ended September 30, 2013.
	Exchange memberships and firm common stocks pledged for clearing purposes are recorded at cost, in accordance with U.S. GAAP and CFTC regulations and are included in ‘other assets’ on the consolidated balance sheets. Equity investments in exchange firm common stock not pledged for clearing purposes are classified as available-for-sale and recorded at fair value, with unrealized gains and losses recorded as a component of OCI, net of tax, until realized. Equity investments in exchange firm common stock not pledged for clearing purposes are included in ‘financial instruments owned’ on the consolidated balance sheets.
	The cost basis for exchange memberships and firm common stock pledged for clearing purposes was $10.4 million and $10.5 million as of September 30, 2013 and 2012, respectively. The fair value of exchange memberships and firm common stock pledged for clearing purposes was $8.5 million and $8.9 million as of September 30, 2013 and 2012, respectively. The fair value of exchange firm common stock is determined by quoted market prices, and the fair value of exchange memberships is determined by recent sale transactions. The Company monitors the fair value of exchange membership seats and firm common stock on a quarterly basis, and does not consider any current unrealized losses on individual exchange memberships to be anything other than a temporary impairment.
	Commodity and Other Repurchase Agreements
	In the normal course of operations the Company accepts notes receivable under sale/repurchase agreements with customers whereby the customers sell certain commodity inventory or other investments and agree to repurchase the commodity inventory or investment at a future date at either a fixed or floating rate. These transactions are short-term in nature, and in accordance with the guidance contained in the Transfers and Servicing Topic of the ASC, are treated as secured borrowings rather than commodity inventory and purchases and sales in the Company’s consolidated financial statements.
Additionally, the Company participates in transactions involving commodities or other investments sold under repurchase agreements (“repos”). In accordance with the guidance contained in the Transfers and Servicing Topic of the ASC, these transactions are treated as secured borrowings that are recorded as a liability in the consolidated balance sheets. Commodities or investments sold under repurchase agreements are reflected at the amount of cash received in connection with the transactions. The Company may be required to provide additional collateral based on the fair value of the underlying asset.
Business Combinations
Acquisitions during fiscal 2013 and fiscal 2012 are accounted for as business combinations in accordance with the provisions of the Business Combinations Topic of the ASC. Under this accounting guidance most of the assets and liabilities acquired and assumed are measured at fair value as of the acquisition date. Certain contingent liabilities acquired require remeasurement at fair value in each subsequent reporting period. Noncontrolling interests are initially measured at fair value and classified as a separate component of equity. Acquisition related costs, such as fees for attorneys, accountants, and investment bankers, are expensed as incurred and are not capitalized as part of the purchase price. For all acquisitions, regardless of the consummation date, deferred tax assets, valuation allowances, and uncertain tax position adjustments occurring after the measurement period are recorded as a component of income, rather than adjusted through goodwill.
Determining the fair value of certain assets and liabilities acquired is subjective in nature and often involves the use of significant estimates and assumptions. Estimating the fair value of the assets and liabilities acquired requires significant judgment.
Contingent Consideration
The Company estimates and records the acquisition date estimated fair value of contingent consideration as part of purchase price consideration for acquisitions. Additionally, each reporting period, the Company estimates changes in the fair value of contingent consideration, and any change in fair value is recognized in the consolidated income statement. An increase in the earn-out expected to be paid will result in a charge to operations in the period that the anticipated fair value of contingent consideration increases, while a decrease in the earn-out expected to be paid will result in a credit to operations in the period that the anticipated fair value of contingent consideration decreases. The estimate of the fair value of contingent consideration requires subjective assumptions to be made of future operating results, discount rates, and probabilities assigned to various potential operating result scenarios. Future revisions to these assumptions could materially change the estimate of the fair value of contingent consideration and, therefore, materially affect the Company’s future financial results.
Additional Paid-In Capital
The Company’s additional paid-in capital (“APIC”) consists of stockholder contributions that are in excess of par value of common stock. Included in APIC are amounts related to the exercise of stock options, share-based compensation and shares held in escrow.
In September 2010, the Company acquired certain assets of Provident Group (“Provident”). The purchase price for the assets and services of the sellers was $5.0 million. Subsequent to closing, the individual sellers placed the entire purchase price into an escrow account and the funds were used to purchase outstanding shares of the Company on the open market. There were 214,325 shares purchased and placed into escrow as a result of this agreement. The entire purchase price was recorded as a reduction in additional paid in capital as shares held in escrow for business combinations. The shares held in escrow for business combinations will be released to the individual sellers, over a five year period from the date of closing based on net profits, in accordance with the provisions of the acquisition agreement. However, if the terms of the agreement are not met, the remaining shares will be forfeited and the remaining shares and balance in the shares held in escrow for business combinations will be recorded as treasury stock. In accordance with the acquisition agreement, 6,799 and 3,255 shares were earned and subsequently released to the sellers during the years ended September 30, 2013 and 2012, respectively.
Revenue Recognition
Sales of physical commodities revenue are recognized when persuasive evidence of an arrangement exists, delivery has occurred, the fee is fixed or determinable, and collectability is reasonably assured. The Company reports its physical commodities revenues on a gross basis, with the corresponding cost of sales shown separately, in accordance with the guidelines provided in the Revenue Recognition Topic of the ASC.
Trading gains, net include brokerage fees and margins generated from OTC derivative trades executed with customers and other counterparties and are recognized when trades are executed. Trading gains, net also include activities where the Company acts as principal in the purchase and sale of individual securities, currencies, commodities or derivative instruments with customers. These transactions may be offset simultaneously with another customer or counterparty, offset with similar but not identical positions on an exchange, made from inventory, or may be aggregated with other purchases to provide liquidity intraday, for a number of days, or in some cases, particularly the base metals business, even longer periods (during which fair value may fluctuate). In addition, trading gains, net includes activities from the Company’s operations of a proprietary foreign exchange desk which arbitrages the futures and cash markets (see additional discussion in the Financial Instruments and Derivatives policy note for revenue recognition on proprietary trading activities). Net dealer inventory and investment gains are recognized on a trade-date basis and include realized gains or losses and changes in unrealized gains or losses on investments at fair value. Dividend income and dividend expense, on short equity positions, are recognized net, in ‘trading gain, net’ on the ex-dividend date.
Commissions on futures contracts are recognized on a half-turn basis in two equal parts. The first half is recognized when the contract is opened and the second half is recognized when the transaction is closed. Commissions on options-on-futures contracts are generally recognized on a half-turn basis, except that full commissions are recognized on options expected to expire without being exercised or offset. Commissions and fees are charged at various rates based on the type of account, the products traded, and the method of trade. Clearing and transaction fees are charged to customers on a per exchange contract basis based on the trade date. Such fees are for clearing customers’ exchange trades and include fees charged to the Company by the various futures exchanges. See discussion of transaction-based clearing expenses below.
Consulting and management fees include risk management consulting fees which are billed and recognized as revenue on a monthly basis when risk management services are provided. Such agreements are generally for one year periods, but are cancelable by either party upon providing thirty days written notice to the other party and the amounts are not variable based on customer trading activities. Asset management fees are recognized as they are earned based on fees due at each period-end date. These include performance fees based on the amount that is due under the formula for exceeding performance targets as of the period-end date. Fee income for structuring and arrangement of debt transactions and management and investment advisory income is recorded when the services related to the underlying transactions are provided and success fees are recorded when complete, as determined under the terms of the assignment or engagement.
Interest income, generated primarily from investments and customer inventory financing, is recognized on an accrual basis. Interest from investments is generated from securities purchased using customer funds deposited with the Company to satisfy margin requirements, net of interest returned to customers, and from securities acquired through internally-generated company funds. Interest also includes unrealized gains and losses on securities owned and those deposited with other parties.
Revenue generally is recognized net of any taxes collected from customers and subsequently remitted to governmental authorities.
Cost of Revenue
Cost of sales of physical commodities include finished commodity or raw material and processing costs along with operating costs relating to the receipt, storage and delivery of the physical commodities.
Compensation and Benefits
Compensation and benefits consists primarily of salaries, incentive compensation, commissions, related payroll taxes and employee benefits. The Company classifies employees as either traders / risk management consultants, operational or administrative personnel, which includes the executive officers. The most significant component of the Company’s compensation expense is the employment of the traders / risk management consultants, who are paid commissions based on the revenues that their customer portfolios generate. The Company accrues commission expense on a trade date basis.
Share-Based Compensation
The Company accounts for share-based compensation in accordance with the guidance of the Compensation-Stock Compensation Topic of the ASC. The cost of employee services received in exchange for a share-based award is generally measured based on the grant-date fair value of the award. Share-based employee awards that require future service are amortized over the relevant service period. Expected forfeitures are included in determining share-based employee compensation expense. In the first quarter of 2006, the Company adopted the guidance under the Compensation-Stock Compensation Topic of the ASC using the modified prospective method. For option awards granted subsequent to the adoption, compensation cost is recognized on a straight-line basis over the vesting period for the entire award. The expense of unvested option awards granted prior to the adoption are recognized on a straight-line basis, over the balance of the vesting period.
Transaction-Based Clearing Expenses
Clearing fees and related expenses include primarily variable expenses for clearing and settlement services, including fees the Company pays to executing brokers, exchanges, clearing organizations and banks. These fees are based on transaction volume, and recorded as expense on the trade date. Clearing fees are passed on to customers and are presented gross in the consolidated statements of income under the Revenue Recognition Topic of the ASC, as the Company acts as a principal for these transactions.
Introducing Broker Commissions
Introducing broker commissions include commissions paid to non-employee third parties that have introduced customers to the Company. Introducing brokers are individuals or organizations that maintain relationships with customers and accept futures and options orders from those customers. The Company directly provides all account, transaction and margining services to introducing brokers, including accepting money, securities and property from the customers. The commissions are determined and settled monthly.
Income Taxes
Income tax expense includes U.S. federal, state and local and foreign income taxes. Certain items of income and expense are not reported in tax returns and financial statements in the same year. The tax effect of such temporary differences is reported as deferred income taxes. Tax provisions are computed in accordance with the Income Taxes Topic of the ASC.
Comprehensive Income
Comprehensive income consists of net income and other gains and losses affecting stockholders’ equity that, under U.S. GAAP, are excluded from net income. Other comprehensive income (loss) includes net actuarial losses from defined benefit pension plans, unrealized gains and losses on available-for-sale securities, gains and losses on foreign currency translations, and changes in the fair value of interest rate swap agreements, to the extent they are, or previously were, effective as cash flow hedges.
Noncontrolling Interest and Variable Interest Entities
In accordance with the Consolidation Topic of the Accounting Standards Codification (“ASC”) the Company consolidates any variable interest entities for which it is the primary beneficiary, as defined. The Company applies the equity method of accounting when the Company does not have a controlling interest in an entity, but exerts significant influence over the entity.
The Company had a majority interest in and was the general partner of the Blackthorn Multi-Advisor Fund, LP (the “Blackthorn Fund”), whose assets, liabilities, income and expenses were included in the Company’s consolidated financial statements. During fiscal 2012, the Company redeemed its remaining investment in Blackthorn Fund effective December 31, 2011. As a result of the final redemption, the Company no longer retains any ownership interests in the Blackthorn Fund, has transferred its rights as general partner and deconsolidated its interest in the Blackthorn Fund as of December 31, 2011. The aggregate of the redemption and remaining noncontrolling interest less the carrying amount of the net assets of the Blackthorn Fund resulted in a nominal gain and was recorded as a component of ‘trading gains, net’ in the consolidated income statement for the year ended September 30, 2012, as a result of the deconsolidation.
Preferred Stock
The Company is authorized to issue one million shares of preferred stock, par value of $0.01 per share, in one or more classes or series to be established by the Company’s board of directors. As of September 30, 2013 and 2012, no preferred shares were outstanding and the Company’s board of directors had not yet established any class or series of shares.
Recent Accounting Pronouncements
In June 2011, the Financial Accounting Standards Board (“FASB”) issued new guidance on the presentation of comprehensive income. This guidance eliminates the option to report comprehensive income and its components in the consolidated statement of stockholders’ equity. Under this guidance, an entity can elect to present items of net income and comprehensive income in one continuous statement or in two separate, but consecutive, statements. In addition, the guidance requires entities to show the effects of items reclassified from accumulated other comprehensive loss to net income on the face of the financial statements. This guidance is effective for fiscal years beginning after December 15, 2011 and interim and annual periods thereafter. Early adoption is permitted, but full retrospective application is required. This guidance was effective for the Company’s fiscal year 2013. The adoption of this guidance resulted in a change in the presentation of comprehensive income in the Company’s consolidated financial statements.
In December 2011, the FASB issued new guidance on the disclosures about offsetting assets and liabilities. 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 expects to adopt this guidance starting with the first quarter of fiscal year 2014. The adoption of this guidance is expected to change some of the Company’s disclosures in the notes to its consolidated financial statements.
In July 2012, the FASB issued final guidance on indefinite-lived intangible assets impairment testing. Under the guidance, entities testing indefinite-lived intangibles for impairment have the option of first performing a qualitative assessment to determine whether it is more likely than not that an indefinite-lived intangible asset is impaired. If a company determines that it is more likely than not that the fair value of such an asset exceeds its carrying amount, it would not need to calculate the fair value of the asset in that year. However, if a company concludes otherwise, it must calculate the fair value of the asset, compare that value with its carrying amount and record an impairment charge, if any. The guidance does not revise the requirement to test indefinite-lived intangible assets annually for impairment. In addition, the guidance does not amend the requirement to test indefinite-lived intangible assets for impairment between annual tests if events or circumstances warrant, however, it does revise the examples of events and circumstances that an entity should consider. The guidance is effective for annual and interim impairment tests performed for fiscal years beginning after September 15, 2012. Early adoption is permitted. The Company adopted this guidance and it did not have a material impact on the Company’s consolidated financial statements.
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 expects to adopt this guidance starting with the first quarter of fiscal year 2014. The adoption of this guidance is not expected to have a material impact on the Company’s 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 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 consolidated financial statements.

Restatement_of_Previously_Issu

Restatement of Previously Issued Financial Statements (Notes)	12 Months Ended
	Sep. 30, 2013
Restatement and Immaterial Correction of Previously Issued Financial Statements [Abstract]	'
Accounting Changes and Error Corrections [Text Block]	'
	Restatement of Previously Issued Financial Statements
	The Company has restated the consolidated financial statements and other financial information for the fiscal years ended September 30, 2012 and 2011, certain financial information for the fiscal year ended September 30, 2010, and for each of the quarters in the fiscal year ended September 30, 2012. In connection with the preparation of the consolidated financial statements for the fiscal year ended September 30, 2013, the Company identified errors in the reconciliation of the Company’s subsidiary INTL FCStone Markets, LLC’s accounting records to its back office system which occurred in 2012, 2011 and 2010. Corrections made by the Company related to these errors in aggregate resulted in a reduction in net income of $5.9 million collectively for the years ended September 30, 2012, 2011 and 2010. The correction of these errors had no impact on the net cash flows related to operating activities, investing activities, or financing activities in the Company’s previously reported consolidated statements of cash flows for the fiscal years ended September 30, 2012 and 2011.
	Financial Statement Presentation
	The prior period consolidated balance sheet included in this filing has been restated to reflect the correction of these reconciliation errors noted above. The impact of the correction of the reconciliation errors to the Company’s previously reported consolidated balance sheet as of September 30, 2012 is summarized below.
	(in millions)	As of September 30, 2012
		(As Reported)		Cumulative Prior Period Adjustments		FY 2012 Adjustment		(As Restated)
	Deposits with and receivables from broker-dealers, clearing organizations and counterparties	$	127.4	(7.1	)	(3.5	)	$	116.8
	Income taxes receivable	$	11.9	2.3		1.3		$	15.5
	Goodwill and intangible assets, net	$	54.7	1.1		—		$	55.8
	Total assets	$	2,958.90	(3.7	)	(2.2	)	$	2,953.00
	Total liabilities	$	2,639.80	—		—		$	2,639.80
	Retained earnings	$	112	(3.7	)	(2.2	)	$	106.1
	Total stockholders’ equity	$	319.1	(3.7	)	(2.2	)	$	313.2
	Total liabilities and stockholders’ equity	$	2,958.90	(3.7	)	(2.2	)	$	2,953.00
	The prior period consolidated income statements included in this filing have been restated to reflect the correction of these reconciliation errors, which impact “trading gains, net” revenues and “income tax expense”. In addition, the prior period consolidated income statements have been revised to reflect the immaterial correction of certain intercompany physical sales which were not correctly eliminated from the consolidated income statements, resulting in a gross-up of sales of physical commodities and cost of sales of physical commodities. This gross-up does not impact operating revenues or net income.
	The prior period consolidated statements of stockholders’ equity included in this filing have been restated as of October 1, 2010 for the cumulative overstatement of retained earnings prior to fiscal year 2011 arising from these errors in the amount of $1.2 million.
	We have reflected the correction of these reconciliation errors in our consolidated financial statements for each of the quarterly periods in the year ended September 30, 2012 as presented in Note 21 - Quarterly Financial Information (Unaudited).
	Immaterial Correction of Errors in Previously Reported Consolidated Financial Statements
	The Company has made an immaterial correction relating to the reconciliation errors for the three months ended June 30, 2013 resulting in an aggregate increase in net income of $0.5 million. The Company has also made immaterial corrections relating to errors involving certain intercompany physical sales which were not correctly eliminated from the consolidated income statements, for the quarterly periods ended December 31, 2012, March 31, 2013, and June 30, 2013. These immaterial corrections did not impact operating revenues or net income.
	The impact of the correction of these errors to the Company's previously reported consolidated income statements for fiscal years ended September 30, 2012 and 2011 is summarized as follows:
		Consolidated Income Statement Information for the Year Ended September 30,
	(in millions, except share and per share amounts)	2012								2011
		(As Reported)		Adjustment		(As Restated)				(As Reported)		Adjustment		(As Restated)
	Sales of physical commodities	$	68,812.50	(1,297.8	)	$	67,514.70			$	75,123.40	(2,602.2	)	$	72,521.20
	Trading gains, net	$	248.4	(3.5	)	$	244.9			$	205.7	(4.1	)	$	201.6
	Total revenues	$	69,260.60	(1,301.3	)	$	67,959.30			$	75,497.60	(2,606.3	)	$	72,891.30
	Cost of sales of physical commodities	$	68,802.90	(1,297.8	)	$	67,505.10			$	75,074.40	(2,602.2	)	$	72,472.20
	Operating revenues	$	457.7	(3.5	)	$	454.2			$	423.2	(4.1	)	$	419.1
	Net operating revenues	$	309.7	(3.5	)	$	306.2			$	312.3	(4.1	)	$	308.2
	Income from continuing operations, before tax	$	19.3	(3.5	)	$	15.8			$	59.5	(4.1	)	$	55.4
	Income tax expense	$	4.4	(1.3	)	$	3.1			$	22.5	(1.6	)	$	20.9
	Net income attributable to INTL FCStone Inc. common stockholders	$	15	(2.2	)	$	12.8			$	37.3	(2.5	)	$	34.8
	Comprehensive income	$	18.7	(2.2	)	$	16.5			$	34.3	(2.5	)	$	31.8
	Basic earnings per share	$	0.79	(0.12	)	$	0.67			$	2.07	(0.14	)	$	1.93
	Diluted earnings per share	$	0.75	(0.11	)	$	0.64			$	1.96	(0.13	)	$	1.83

Earnings_per_Share_Notes

Earnings per Share (Notes)	12 Months Ended
	Sep. 30, 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.
		Year Ended September 30,
	(in millions, except share amounts)	2013			2012			2011
					(As Restated)			(As Restated)
	Numerator:
	Income from continuing operations attributable to INTL FCStone Inc. stockholders	$	19.3		$	12.8		$	34.6
	Less: Allocation to participating securities	(0.8		)	(0.5		)	(0.9		)
	Income from continuing operations allocated to common stockholders	$	18.5		$	12.3		$	33.7
	Income from discontinued operations	$	—		$	—		$	0.2
	Less: Allocation to participating securities	—			—			—
	Income from discontinued operations allocated to common stockholders	$	—		$	—		$	0.2
	Diluted net income	$	19.3		$	12.8		$	34.8
	Less: Allocation to participating securities	(0.8		)	(0.5		)	(0.9		)
	Diluted net income allocated to common stockholders	$	18.5		$	12.3		$	33.9
	Denominator:
	Weighted average number of:
	Common shares outstanding	18,443,233			18,282,939			17,618,085
	Dilutive potential common shares outstanding:
	Share-based awards	625,264			873,960			949,369
	Diluted weighted-average shares	19,068,497			19,156,899			18,567,454
	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 ASC.
	Options to purchase 1,447,688, 1,157,601 and 386,031 shares of common stock for fiscal years ended 2013, 2012 and 2011, 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)	12 Months Ended
	Sep. 30, 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 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
	•	Payable to customers
	•	Payable to broker-dealers, clearing organizations and counterparties
	•	Financial instruments sold, not yet purchased
	Fair Value Hierarchy
	As required by the Fair Value Measurements and Disclosures Topic of the ASC, financial and nonfinancial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). A market is active if there are sufficient transactions on an ongoing basis to provide current pricing information for the asset or liability, pricing information is released publicly, and price quotations do not vary substantially either over time or among market makers. Observable inputs reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from sources independent of the reporting entity. The guidance requires the Company to consider counterparty credit risk of all parties to outstanding derivative instruments that would be considered by a market participant in the transfer or settlement of such contracts (exit price). The Company’s exposure to credit risk on derivative financial instruments relates to the portfolio of OTC derivative contracts as all exchange-traded contracts held can be settled on an active market with the credit guarantee by the respective exchange. The Company requires each counterparty to deposit margin collateral for all OTC instruments and is also required to deposit margin collateral with counterparties. The Company has assessed the nature of these deposits and used its discretion to adjust each based on the underlying credit considerations for the counterparty and determined that the collateral deposits minimize the exposure to counterparty credit risk in the evaluation of the fair value of OTC instruments as determined by a market participant.
	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, mutual funds and investments in managed 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. 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 $46.4 million (carrying value of $45.5 million) as of September 30, 2013, based on the transaction prices at public exchanges for the same or similar issues.
	The fair value estimates presented herein are based on pertinent information available to management as of September 30, 2013 and 2012. 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 financial statements since that date and current estimates of fair value may differ significantly from the amounts presented herein.
	Cash equivalents, securities, commodities warehouse receipts, derivative financial instruments 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 years ended September 30, 2013 and 2012. 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 1 consists of financial assets and liabilities whose fair values are estimated using quoted market prices. Included in Level 1 are money market funds, certificates of deposit, commodities warehouse receipts, common stock and American Depositary Receipts (“ADRs”), some U.S. and foreign obligations, equity investments in exchange firms, some mutual funds, as well as futures and options-on-futures contracts traded on national exchanges, exchange-cleared swaps and options which are valued using exchange closing prices, and OTC swaps and options contracts using quoted prices from national exchanges in which the Company executes transactions for customer and proprietary accounts;
	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. Included in Level 2 are those financial assets and liabilities for which fair values are estimated using models or other valuation methodologies. These models are primarily industry-standard models that consider various observable inputs, including time value, yield curve, volatility factors, observable current market and contractual prices for the underlying financial instruments, as well as other relevant economic measures. Included in Level 2 are U.S. and foreign government obligations, mortgage-backed securities, some common stock and ADRs, corporate and municipal bonds, some mutual funds, investments in managed funds and OTC forwards, swaps, and options; 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). Level 3 comprises financial assets and liabilities whose fair value is estimated based on internally developed models or methodologies utilizing significant inputs that are not readily observable from objective sources. Included in Level 3 are common stock and ADRs, some corporate and municipal bonds, some other investments and contingent liabilities.
	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 September 30, 2013 and September 30, 2012 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 September 30, 2013 and 2012.
		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
	U.S. government obligations	—			—			—			—			—
	Derivatives	1.8			0.2			—			(15.1		)	(13.1		)
	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 are included in that level.
		September 30, 2012
	(in millions)	Level 1			Level 2			Level 3			Netting and			Total
Collateral
-1
Assets:
Money market funds	$	0.1		$	—		$	—		$	—		$	0.1
Certificate of deposits	10.4			—			—			—			10.4
Unrestricted cash equivalents	10.5			—			—			—			10.5
Commodities warehouse receipts	22.3			—			—			—			22.3
U.S. government obligations	—			50.5			—			—			50.5
Securities and other assets segregated under federal and other regulations	22.3			50.5			—			—			72.8
Money market funds	335.1			—			—			—			335.1
U.S. government obligations	—			1,318.30			—			—			1,318.30
Mortgage-backed securities	—			7			—			—			7
Derivatives	3,344.30			—			—			(3,494.7		)	(150.4		)
Deposits and receivables from exchange-clearing organizations	3,679.40			1,325.30			—			(3,494.7		)	1,510.00
Derivatives	0.7			5			—			(6.4		)	(0.7		)
Deposits and receivables from broker-dealers, clearing organizations and counterparties - derivatives	0.7			5			—			(6.4		)	(0.7		)
Common and preferred stock and American Depositary Receipts (“ADRs”)	17.8			5.6			0.9			—			24.3
Exchangeable foreign ordinary equities and ADRs	10			—			—			—			10
Corporate and municipal bonds	0.3			0.6			3.6			—			4.5
U.S. government obligations	—			0.3			—			—			0.3
Foreign government obligations	14.8			—			—			—			14.8
Derivatives	315.6			785.3			—			(1,047.0		)	53.9
Commodities leases	—			135.2			—			(93.1		)	42.1
Commodities warehouse receipts	7.5			—			—			—			7.5
Exchange firm common stock	3.4			9			—			—			12.4
Mutual funds and other	1.9			—			—			—			1.9
Financial instruments owned	371.3			936			4.5			(1,140.1		)	171.7
Total assets at fair value	$	4,084.20		$	2,316.80		$	4.5		$	(4,641.2	)	$	1,764.30
Liabilities:
Accounts payable and other accrued liabilities - contingent liabilities	$	—		$	—		$	14.8		$	—		$	14.8
Payable to customers - derivatives	3,562.30			—			—			(3,562.3		)	—
Common and preferred stock and ADRs	16.4			5.9			—			—			22.3
Exchangeable foreign ordinary equities and ADRs	5.7			—			—			—			5.7
Derivatives	338.1			775.2			—			(1,068.7		)	44.6
Commodities leases	—			220			—			(117.2		)	102.8
Financial instruments sold, not yet purchased	360.2			1,001.10			—			(1,185.9		)	175.4
Total liabilities at fair value	$	3,922.50		$	1,001.10		$	14.8		$	(4,748.2	)	$	190.2
-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 are included in that level.
Realized and unrealized gains and losses are included in ‘trading gains, net’ in the consolidated income statements.
Information on Level 3 Financial Assets and Liabilities
The Company’s financial assets at fair value classified within level 3 of the fair value hierarchy as of September 30, 2013 and 2012 are summarized below:
(in millions)	September 30, 2013			September 30, 2012
Total level 3 assets	$	4.2		$	4.5
Level 3 assets for which the Company bears economic exposure	$	4.2		$	4.5
Total assets	$	2,848.00		$	2,953.00
Total financial assets at fair value	$	1,627.70		$	1,764.30
Total level 3 assets as a percentage of total assets	0.1		%	0.2		%
Level 3 assets for which the Company bears economic exposure as a percentage of total assets	0.1		%	0.2		%
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 fiscal years ended September 30, 2013 and 2012, including a summary of unrealized gains (losses) during the fiscal year ended on the Company’s level 3 financial assets and liabilities still held as of September 30, 2013.
	Level 3 Financial Assets and Financial Liabilities
	For the Year Ended September 30, 2013
(in millions)	Balances at			Realized gains			Unrealized			Purchases/			Settlements			Transfers in		Balances at
	beginning of			(losses) during			gains (losses)			issuances						or (out) of		end of period
	period			period			during period									Level 3
Assets:
Common and preferred stock and ADRs	$	0.9		$	—		$	(0.2	)	$	—		$	—		$	—	$	0.7
Corporate and municipal bonds	3.6			—			(0.1		)	—			—			—		3.5
	$	4.5		$	—		$	(0.3	)	$	—		$	—		$	—	$	4.2
Liabilities:
Contingent liabilities	$	14.8		$	—		$	2.6		$	5.6		$	(13.4	)	$	—	$	9.6
	Level 3 Financial Assets and Financial Liabilities
	For the Year Ended September 30, 2012
(in millions)	Balances at			Realized gains			Unrealized			Purchases/			Settlements			Transfers in		Balances at
	beginning of			(losses) during			gains (losses)			issuances						or (out) of		end of period
	period			period			during period									Level 3
Assets:
Common and preferred stock and ADRs	$	1.1		$	—		$	(0.2	)	$	—		$	—		$	—	$	0.9
Corporate and municipal bonds	3.6			—			—			—			—			—		3.6
Mutual funds and other	0.4			(0.4		)	—			—			—			—		—
	$	5.1		$	(0.4	)	$	(0.2	)	$	—		$	—		$	—	$	4.5
Liabilities:
Contingent liabilities	$	22.3		$	—		$	2		$	0.1		$	(9.6	)	$	—	$	14.8
In accordance with the Fair Value MeasurementsTopic 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 September 30, 2013, the Company’s investment in the hotel is $3.5 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. During the year ended September 30, 2011, the Company recorded a loss of $1.7 million, representing an other than temporary impairment. 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 years ended September 30, 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 September 30, 2013, certain acquisitions have had changes in the estimates of undiscounted cash flows, based on actual performances fluctuating from estimates. During the fiscal years ended September 30, 2013 and 2012, the fair value of the contingent consideration increased $2.6 million and $2.0 million, with the corresponding expense classified as ‘other’ in the consolidated income statements.
The value of an exchange-traded derivative contract is equal to the unrealized gain or loss on the contract determined by marking the contract to the current settlement price for a like contract on the valuation date of the contract. A settlement price may not be used if the market makes a limit move with respect to a particular derivative contract or if the securities underlying the contract experience significant price fluctuations after the determination of the settlement price. When a settlement price cannot be used, derivative contracts will be valued at their fair value as determined in good faith pursuant to procedures adopted by management of the Company.
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.
On March 31, 2013, the commodities market experienced downward limit price movements on certain commodities. As a result, certain exchange-traded derivative contracts, which would normally be valued using quoted market prices and classified as level 1 within the fair value hierarchy, were priced using a valuation model using observable inputs. Due to the change in valuation techniques because of the limit moves, some derivative assets and liabilities were classified as level 2 at March 31, 2013. Such derivative assets and liabilities were valued using quoted market prices, and as such, were classified as level 1 as of June, 30, 2013, September 30, 2013 and prior to March 31, 2013. There were no significant similar occurrences of upward or downward limit price movements during the year ended September 30, 2012 and the derivative assets and liabilities were valued using quoted market prices as of the respective quarter ends in fiscal year 2012 and as such were classified as level 1.
Except as described above, the Company did not have any additional significant transfers between level 1 and level 2 fair value measurements for the fiscal years ended September 30, 2013 and 2012.
The Company has 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 OCI until realized. As of September 30, 2013, the cost and fair value of the equity investments in exchange firms is $3.7 million and $4.4 million, respectively. As of September 30, 2012, the cost and fair value of the equity investments in exchange firms is $4.4 million and $12.4 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 fiscal year ended September 30, 2013, 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 consolidated balance sheet. The Company received proceeds of $1.5 million and recognized a gain of $0.9 million before taxes, during the fiscal year ended September 30, 2013, in connection with the sale of these seats.
The Company has unrealized losses of $0.5 million, net of income tax benefit of $0.3 million and unrealized gains of $6.2 million, net of income tax expense of $2.0 million 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 as of September 30, 2013 and 2012, respectively. The Company monitors the fair value of exchange common stock on a periodic basis, and does not consider any current unrealized losses to be anything other than temporary impairment.
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 September 30, 2013 and September 30, 2012:
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, is less than 0.1 million.
September 30, 2012
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	$	1,298.90		$	—		$	—		$	1,298.90
Mortgage-backed securities	6.8			0.1			—			6.9
	$	1,305.70		$	0.1		$	—		$	1,305.80
-1	Unrealized gain/loss on U.S. government obligations as of September 30, 2012, is less than 0.1 million.
As of September 30, 2013 and September 30, 2012, investments in debt securities classified as available-for-sale (AFS) mature as follows:
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
September 30, 2012
	Due in						Estimated
(in millions)	Less than 1 year			1 year or more			Fair Value
U.S. government obligations	$	1,298.90		$	—		$	1,298.90
Mortgage-backed securities	—			6.9			6.9
	$	1,298.90		$	6.9		$	1,305.80
Except as discussed previously, there were no other sales of AFS Securities during years ended September 30, 2013 and September 30, 2012, and as a result, no additional realized gains or losses were recorded for the years ended September 30, 2013 and September 30, 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)	12 Months Ended
	Sep. 30, 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 consolidated financial statements as of September 30, 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 September 30, 2013. The total of $179.9 million as of September 30, 2013 includes $30.7 million for derivative contracts, which represent a liability to the Company based on their fair values as of September 30, 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 consolidating 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. At September 30, 2012, the Company had $765.0 million in notional principal of interest rate swaps outstanding with a weighted-average remaining life of 6 months. The last remaining interest rate swap expired in the fourth quarter of 2013. The Company did not have any interest rate swaps outstanding at September 30, 2013.
	Listed below are the fair values of the Company’s derivative assets and liabilities as of September 30, 2013 and 2012. Assets represent net unrealized gains and liabilities represent net unrealized losses.
		September 30, 2013						September 30, 2012
	(in millions)	Assets (1)			Liabilities (1)			Assets (1)			Liabilities (1)
	Derivative contracts not accounted for as hedges:
	Exchange-traded commodity derivatives	$	2,036.60		$	2,046.30		$	3,325.60		$	3,565.30
	OTC commodity derivatives	481.4			484.9			823.6			841.4
	Exchange-traded foreign exchange derivatives	89.3			104.2			63			47.7
	OTC foreign exchange derivatives	132.3			162.3			215.4			196.6
	Exchange-traded interest rate derivatives	4.3			36			0.9			2.6
	OTC interest rate derivatives	—			—			1.6			—
	Equity index derivatives	135.5			141.7			20.8			22
	Gross fair value of derivative contracts	2,879.40			2,975.40			4,450.90			4,675.60
	Impact of netting and collateral	(2,940.4		)	(2,944.7		)	(4,548.1		)	(4,631.0		)
	Total fair value included in ‘Deposits and receivables from exchange-clearing organizations’	$	(69.8	)				$	(150.4	)
	Total fair value included in ‘Deposits and receivables from broker-dealers, clearing organizations and counterparties’	$	(13.1	)				$	(0.7	)
	Total fair value included in ‘Financial instruments owned, at fair value’	$	21.9					$	53.9
	Fair value included in ‘Financial instruments sold, not yet purchased, at fair value’				$	30.7					$	44.6
	-1	As of September 30, 2013 and 2012, the Company’s derivative contract volume for open positions was approximately 4.1 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 option products, including combinations of buying and selling puts and calls. The Company mitigates its risk by generally offsetting the customer’s transaction simultaneously with one of the Company’s trading counterparties or will offset that transaction 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 net gains (losses) related to derivative financial instruments for the fiscal years ended September 30, 2013, 2012 and 2011, in accordance with the Derivatives and Hedging Topic of the ASC. The net gains (losses) set forth below are included in ‘trading gains, net’ in the consolidated income statements.
		Year Ended September 30,
	(in millions)	2013			2012			2011
					(As Restated)			(As Restated)
	Commodities	$	84.6		$	62.3		$	32.8
	Foreign exchange	11.6			10.4			15
	Interest rate	0.1			1.4			3.5
	Net gains from derivative contracts	$	96.3		$	74.1		$	51.3
	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 September 30, 2013 and September 30, 2012 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 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)	12 Months Ended
	Sep. 30, 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 $1.1 million and 0.9 million as of September 30, 2013 and 2012, respectively. The allowance for doubtful accounts related to notes receivable was $0.1 million as of September 30, 2013 and 2012.
	During the year ended September 30, 2013, the Company recorded bad debt expense, net of recoveries, of $0.7 million, including provision increases of $0.2 million and direct write-offs of $0.6 million, offset by recoveries of $0.1 million. The provision increases during fiscal 2013 were primarily related to customer deficits in the C&RM segment, and the direct write-offs were primarily related to investment banking advisory services in the Securities segment.
	During the year ended September 30, 2012, the Company recorded bad debt expense, net of recoveries, of $0.7 million, including provision increases of $0.5 million and direct write-offs of $0.3 million, offset by recoveries of $0.1 million. The provision increase during fiscal 2012 was primarily related to customer deficits in the C&RM segment. During fiscal 2012, the Company charged-off receivables on consigned gold transactions of $8.5 million and CES customer deficits of $2.7 million, which were all fully reserved.
	During the year ended September 30, 2011, the Company recorded bad debt expense, net of recoveries, of $4.5 million, including provision increases of $6.8 million and direct write-offs of $1.4 million, offset by recoveries of $3.7 million. The provision increase during fiscal 2011 was primarily related to credit losses recognized on consigned gold transactions, in the C&RM segment, and a clearing customer deficit account in the CES segment. During fiscal 2011, the Company recovered $3.7 million of bad debt expense related to collection of a previous customer account deficit, in the C&RM segment, and collection following a settlement relating to a disputed trade, in the CES segment, that was “given-up” to FCStone, LLC during the quarter ended June 30, 2010 by another FCM. During fiscal 2011, the Company charged off $111.5 million of note receivable which was fully reserved. The remaining notes receivable related to these customer account deficits is $0.7 million, and the Company expects to collect the remaining amounts from the introducing broker, by withholding commissions due on future revenues collected by the Company, although no assurance can be given as to the timing of collection.
	Activity in the allowance for doubtful accounts and notes for the years ended September 30, 2013, 2012 and 2011 was as follows:
	(in millions)	2013		2012			2011
	Balance, beginning of year	$	1	$	11.9		$	119.2
	Provision for bad debts	0.2		0.4			7.2
	Transfer in (1)	—		—			2.5
	Deductions:
	Charge-offs	—		(11.2		)	(113.3		)
	Recoveries	—		(0.1		)	(3.7		)
	Balance, end of year	$	1.2	$	1		$	11.9
	-1	During the three months ended December 31, 2010, certain open position derivative contracts, which had a $2.5 million credit reserve as of September 30, 2010 were closed, and the deficit account balance was reclassified from financial instruments owned to a receivable from customer. Accordingly, the previously established credit reserve amount was transferred into the allowance for doubtful accounts during the three months ended December 31, 2010.
	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 $21.1 million and $10.2 million as of September 30, 2013 and 2012, respectively. The Company has sold $18.7 million and $0.8 million of the insured portion of the notes through non-recourse participation agreements with other third parties as of September 30, 2013 and 2012, respectively.
	See discussion of notes receivable related to commodity repurchase agreements in Note 14.

Physical_Commodities_Inventory

Physical Commodities Inventory (Notes)	12 Months Ended
	Sep. 30, 2013
Physical Commodities Inventory [Abstract]	'
Inventory Disclosure [Text Block]	'
	Physical Commodities Inventory
	The carrying values of the Company’s inventory as of September 30, 2013 and 2012 are shown below.
	(in millions)	September 30,		September 30, 2012
		2013
	Commodities in process	$	—	$	13.6
	Finished commodities	59		118
	Physical commodities inventory	$	59	$	131.6
	As a result of declining market prices for some commodities towards the end of the fiscal year, the Company has recorded LCM adjustments for physical commodities inventory of $0.9 million and $0.4 million as of September 30, 2013 and 2012, respectively. The adjustments are included in ‘cost of sales of physical commodities’ in the consolidated income statements.

Property_and_Equipment_net

Property and Equipment, net	12 Months Ended
	Sep. 30, 2013
Property and Equipment, net [Abstract]	'
Property, Plant and Equipment Disclosure [Text Block]	'
	Property and Equipment, net
	Property and equipment are stated at cost, and reported net of accumulated depreciation on the consolidated balance sheets. Depreciation on plant and equipment is calculated on the straight-line method over the estimated useful lives of the assets. The estimated useful lives of property and equipment range from 3 to 10 years. During the fiscal years ended September 30, 2013, 2012 and 2011, depreciation expense was $5.8 million, $4.7 million and $2.4 million, respectively.
	A summary of property and equipment, at cost less accumulated depreciation as of September 30, 2013 and 2012 is as follows:
	(in millions)	September 30, 2013			September 30, 2012
	Property and equipment:
	Furniture and fixtures	$	6		$	6.3
	Software	6			3.9
	Equipment	10.2			9.3
	Leasehold improvements	9.6			9
	Total property and equipment	31.8			28.5
	Less accumulated depreciation	(14.3		)	(9.6		)
	Property and equipment, net	$	17.5		$	18.9

Goodwill_Notes

Goodwill (Notes)	12 Months Ended
	Sep. 30, 2013
Goodwill [Abstract]	'
Goodwill Disclosure [Text Block]	'
	Goodwill
	During the fiscal years ended September 30, 2013 and 2012, the Company recognized $2.8 million and $1.1 million, respectively, in additional goodwill related to acquisitions. See discussion in Note 19 related to the additional goodwill recorded for the Company’s acquisitions.
	Goodwill allocated to the Company’s operating segments as of September 30, 2013 and 2012 is as follows:
	(in millions)	September 30,		September 30,
		2013		2012
				(As Restated)
	Commodity and Risk Management Services	$	33.1	$	33.1
	Foreign Exchange	6.3		6.3
	Securities	8.1		5.3
	Goodwill	$	47.5	$	44.7

Intangible_Assets_Notes

Intangible Assets (Notes)	12 Months Ended
	Sep. 30, 2013
Intangible Assets [Abstract]	'
Intangible Assets Disclosure [Text Block]	'
	Intangible Assets
	Intangible assets of $2.8 million, attributed to customer relationships, acquired during the fiscal year ended September 30, 2013 relate to an acquisition, as discussed in Note 19.
	The gross and net carrying values of intangible assets as of the balance sheet dates, by major intangible asset class are as follows:
		September 30, 2013							September 30, 2012
	(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	)	$	—	$	3.7	$	(3.0	)	$	0.7
	Trade name	0.7		(0.7		)	—		0.7		(0.5		)	0.2
	Software programs/platforms	2.2		(1.5		)	0.7		2.2		(1.0		)	1.2
	Customer base	12.4		(2.6		)	9.8		9.6		(1.8		)	7.8
		19		(8.5		)	10.5		16.2		(6.3		)	9.9
	Intangible assets not subject to amortization
	Trade name	1.1		—			1.1		1.2		—			1.2
	Total intangible assets	$	20.1	$	(8.5	)	$	11.6	$	17.4	$	(6.3	)	$	11.1
	Amortization expense related to intangible assets was $2.2 million, $2.5 million, and $2.3 million for the fiscal years ended 2013, 2012 and 2011, respectively.
	As of September 30, 2013, the estimated future amortization expense was as follows:
	(in millions)
	Fiscal 2014	$	1.4
	Fiscal 2015	1
	Fiscal 2016	0.7
	Fiscal 2017	0.7
	Fiscal 2018	0.7
	Fiscal 2019 and thereafter	6
		$	10.5
	During the fiscal years ended September 30, 2013 and 2012, as part of the annual goodwill and intangible assets impairment analysis, the Company assessed the value of the indefinite-lived trade names related to previous acquisitions and determined that the value of the Hanley Companies, Hencorp Futures and Provident Group trade names had been impaired during those years. The Company discontinued the use of those trade names, which impaired the value of the previously recorded intangible assets. The remaining value, if any, of the trade names was determined based on the income approach utilizing projected sales, an estimated royalty rate and discount rate.
	The Company recorded impairment losses for the trade names of $0.1 million and $0.8 million, in ‘bad debts and impairments’ on the consolidated income statements, during the fiscal years ended September 30, 2013 and 2012. During fiscal year 2012, the Company determined that the remaining value of the Hencorp Futures trade name was no longer an indefinite-lived intangible asset. The remaining value of the Hencorp Futures trade name of $0.1 million was amortized over a one year period. The Hanley Companies, Hencorp Futures and Provident Group trade names were recorded in the CR&M and Securities segments, respectively.

Credit_Facilities_Notes

Credit Facilities (Notes)	12 Months Ended
	Sep. 30, 2013
Credit Facilities [Abstract]	'
Debt Disclosure [Text Block]	'
	Credit Facilities
	Variable-Rate Credit Facilities
	The Company has three committed credit facilities under which the Company and its subsidiaries may borrow up to $290.0 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 are as follows:
	A three-year syndicated committed loan facility established on September 20, 2013 under which $140 million is available to the Company for general working capital requirements. The line of credit is secured by a pledge of shares held in certain of the Company’s subsidiaries. Unused portions of the loan facility require a commitment fee of 0.625% on the unused commitment. Borrowings under the facility bear interest at the Eurodollar Rate, as defined, plus 3.00% or Base Rate, as defined, plus 2.00%, and averaged 3.72% as of September 30, 2013. The agreement contains financial covenants related to consolidated tangible net worth, consolidated domestic tangible net worth, consolidated interest coverage ratio and consolidated net unencumbered liquid assets, as defined. The Company was in compliance with these financial covenants as of September 30, 2013. The agreement also includes a non-financial covenant that requires the Company to provide audited financial statements for the fiscal year ended September 30, 2013 within ninety days after the end of the fiscal year. The Company was unable to deliver the audited financial statements 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 has to provide the audited financial statements through January 31, 2014. The Company paid debt issuance costs of $1.5 million in connection with the issuance of this credit facility, which are being amortized over the thirty-six month term of the facility.
	An unsecured syndicated committed line of credit, established on June 21, 2010 and renewed by amendment on April 11, 2013, under which $75 million is available to the Company’s subsidiary, FCStone, LLC to provide short term funding of margin to commodity exchanges as necessary. This line of credit is subject to annual review, and the continued availability of this line of credit is subject to FCStone, LLC’s financial condition and operating results continuing to be satisfactory as set forth in the agreement. Unused portions of the margin line require a commitment fee of 0.50% on the unused commitment. Borrowings under the margin line are on a demand basis and bear interest at the Base Rate, as defined, plus 2.00%, which was 5.25% as of September 30, 2013. The agreement contains financial covenants related to FCStone, LLC’s tangible net worth, leverage ratio, and net capital, as defined. FCStone, LLC was in compliance with these covenants as of September 30, 2013. The facility is guaranteed by the Company.
	A syndicated committed borrowing facility established on August 10, 2012, and amended on July 30, 2013, under which $75.0 million is available to the Company’s subsidiary, FCStone Merchant Services, LLC (“FCStone Merchants”) for financing traditional commodity financing arrangements and commodity repurchase agreements. The facility is secured by the assets of FCStone Merchants, and guaranteed by the Company. Unused portions of the borrowing facility require a commitment fee of 0.50% on the unused commitment. The borrowings outstanding under the facility bear interest at a rate per annum equal to the Base Rate plus Applicable Margin, as defined, which averaged 3.75% as of September 30, 2013. The agreement contains financial covenants related to tangible net worth, as defined. FCStone Merchants was in compliance with this covenant as of September 30, 2013. FCStone Merchants paid minimal debt issuance costs in connection with this credit facility.
	Senior Unsecured Notes
	On July 22, 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 “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, beginning on October 30, 2013). The Notes will 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 September 30, 2013 on the facilities, and outstanding borrowings on the facilities as well as indebtedness on senior notes as of September 30, 2013 and 2012:
	(in millions)
	Credit Facilities						Amounts Outstanding
		Borrower	Security	Renewal / Expiration Date	Total		September 30,		September 30,
					Commitment		2013		2012
		INTL FCStone Inc.	Certain pledged shares	September 20, 2016	$	140	$	55	$	48
		FCStone, LLC	None	April 10, 2014	75		—		20
		FCStone Merchants	Certain commodities assets	May 1, 2014	75		6		43.2
		INTL Commodities	Certain commodities assets	Expired July 31, 2013	—		—		107
					$	290	61		218.2
	Senior Unsecured Notes
		8.50% senior notes, due July 30, 2020					45.5		—
	Total indebtedness						$	106.5	$	218.2
	As noted above, $150 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.
	Subsequent to September 30, 2013, the Company’s subsidiary, INTL FCStone Ltd. established a credit facility under which $25.0 million is available to provide short term funding of margin to commodity exchanges as necessary, and for general corporate purposes of INTL FCStone, Ltd (see Note 23).

Commitments_and_Contingencies_

Commitments and Contingencies (Notes)	12 Months Ended
	Sep. 30, 2013
Commitments and Contingencies [Abstract]	'
Commitments and Contingencies Disclosure [Text Block]	'
	Commitments and Contingencies
	Legal Proceedings
	Certain conditions may exist as of the date 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 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 September 30, 2013 and 2012, the consolidated balance sheets include loss contingency accruals, recorded during and prior to these fiscal years then ended, 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
	FCStone and certain officers of FCStone were defendants in an action filed in the United States District Court for the Western District of Missouri in July 2008. Plaintiffs subsequently filed a consolidated amended complaint (“CAC”) in September 2009. As alleged in the CAC, the action purports to be brought as a class action on behalf of purchasers of FCStone common stock between November 15, 2007 and February 24, 2009. The CAC seeks to hold defendants liable under Section 10(b) and Section 20(a) of the Securities Exchange Act of 1934 and concerns disclosures included in FCStone’s fiscal year 2008 public filings. Specifically, the CAC relates to FCStone’s public disclosures regarding an interest rate hedge, a bad debt expense arising from unprecedented events in the cotton trading market, and certain disclosures beginning on November 3, 2008 related to losses it expected to incur arising primarily from a customer energy trading account. FCStone and the named officers moved to dismiss the action. The parties to the litigation reached an agreement in principle to settle this matter during May 2012, which was approved by order of the court on July 23, 2013. The settlement was at no cost to the Company after consideration of insurance.
	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:
	•	cease and desist from violating CFTC Regulation 166.3;
	•	pay $1.5 million to the CFTC; and
	•	appoint an independent third party reviewer to review and evaluate FCStone, LLC’s existing policies and procedures relating to certain risks, to ensure that the Company has made sufficient modifications to its risk controls since 2008.
	The fine of $1.5 million was paid in full in fiscal 2013. Also, the Company has appointed an independent third party to conduct the aforementioned review of policies and procedures, and that review is currently in process.
	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 $9.6 million and $14.8 million are included in ‘accounts payable and other accrued liabilities’ in the consolidated balance sheets as of September 30, 2013 and 2012, respectively. 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 years ended September 30, 2013, 2012 and 2011 were increases of $2.6 million, $2.0 million and $3.1 million, respectively, and are included in ‘other’ in the consolidated income statements.
	The Company recorded an estimated contingent liability as of the acquisition date, which was also the estimated total purchase price, of $5.6 million, relating to the December 2012 acquisition of the accounts of Tradewire Securities, LLC, as described in Note 19. The Company expects to make cash payments of $0.9 million, $2.0 million and $5.5 million in fiscal 2014, 2015, and 2016, respectively, related to this contingent liability. The change in fair value during the year ended September 30, 2013 was an increase of $0.7 million, included in ‘other’ in the consolidated income statement. The present value of the estimated total purchase price, including contingent consideration, is $6.3 million as of September 30, 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, see Note 19 for discussion of the acquisition. The acquisition date fair value of additional consideration was estimated to be $0.1 million. The present value of the estimated contingent liability recorded of $0.1 million as of September 30, 2013 represents the fair value of the expected consideration to be paid, based on the forecasted adjusted pre-tax net earnings for the third fiscal year following the closing of the acquisition, plus an additional final contingent payment.
	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, (“Hencorp Futures”), which may result in the payment of additional purchase price consideration, see Note 19 for discussion of the acquisition. The acquisition date fair value of additional consideration was estimated to be $2.3 million. The contingent liability recorded as of September 30, 2013 represents an estimated contingent payment of $0.7 million based on adjusted pre-tax net earnings of Hencorp Futures for fiscal 2013 and 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 those future payments. The Company expects to make remaining cash payments of $0.7 million and $2.8 million in fiscal 2014 and 2015, respectively, related to this contingent liability. The change in fair value during the years ended September 30, 2013 and 2012 were increases of $1.0 million and $0.1 million, respectively, and are included in ‘other’ in the consolidated income statements. The present value of the estimated total purchase price, including contingent consideration, is $7.5 million as of September 30, 2013, of which $3.2 million has not been paid and is included in ‘accounts payable and other accrued liabilities’ in the consolidated balance sheet.
	In July 2013, the Company paid $10.0 million, representing the final payment relating to the July 2010 acquisition of the Hanley Companies, which was reflected as a contingent liability in ‘accounts payable and other liabilities’ in the previous consolidated balance sheet. The change in fair value, related to that contingent liability, for the years ended September 30, 2013 and 2012 were increases of $0.7 million and $2.0 million, respectively, and are included in ‘other’ in the consolidated income statements.
	In May 2013, the Company paid $3.1 million, representing the final payment relating to the April 2010 acquisition of the RMI Companies, subsequently reorganized as divisions of FCStone, LLC, which was reflected as a contingent liability in ‘accounts payable and other liabilities’ in the previous consolidated balance sheet. The change in fair value, related to that contingent liability, for the fiscal years ended September 30, 2013 and 2012 were an increase of $0.2 million and decrease of $28 thousand, respectively, and are included in ‘other’ in the consolidated income statements.
	The Company had a contingent liability relating to the February 2008 acquisition of Globecot, Inc. Under the terms of the purchase agreement, the Company had an obligation to pay additional consideration if specific conditions and earnings targets were met in the twelve-month period ending January 31, 2013. As a result of the Company’s acquisition of FCStone Group, Inc. and subsidiaries (the “FCStone transaction”), effective September 30, 2009, any additional consideration paid as a result of this acquisition would be considered an adjustment to a pre-acquisition contingency, made after the end of the allocation period, and included in earnings in the current period. The final pre-acquisition contingency expense of $0.4 million was recorded during fiscal year ended September 30, 2013 and there are no further contingent payments relating to the Globecot acquisition.
	Operating Leases
	The Company is obligated under various noncancelable operating leases for the rental of office facilities, aircraft, automobiles, service obligations and certain office equipment, and accounts for these lease obligations on a straight line basis. The expense associated with operating leases amounted to $9.2 million, $8.9 million and $7.2 million, for fiscal years ended 2013, 2012 and 2011, respectively. The expenses associated with the operating leases and service obligations are reported in the consolidated income statements in ‘occupancy and equipment rental’, ‘transaction-based clearing expenses’ and ‘other’ expenses.
	Future aggregate minimum lease payments under noncancelable operating leases as of September 30, 2013 are as follows:
	(in millions)
	Year ending September 30,
	2014	$	6.7
	2015	5.8
	2016	4.5
	2017	4
	2018	3.7
	Thereafter	10.2
		$	34.9
	Purchase Commitments
	The Company determines an estimate of contractual purchase commitments in the ordinary course of business primarily for the purchase of precious metals. Unpriced contract commitments have been estimated using September 30, 2013 fair values. The purchase commitments and other obligations as of September 30, 2013 for less than one year, one to three years and three to five years were $298.7 million, $6.8 million and $3.4 million, respectively. There were $1.6 million purchase commitments and other obligations after five years as of September 30, 2013. The purchase commitments for less than one year will be partially offset by corresponding sales commitments of $216.6 million.
	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 consolidated financial statements for these agreements and believes that any potential requirement to make payments under these agreements is remote.

Regulatory_Requirements_and_Su

Regulatory Requirements and Subsidiary Dividend Restrictions (Notes)	12 Months Ended
	Sep. 30, 2013
Capital and Other Regulatory Requirements [Abstract]	'
Regulatory Capital Requirements under Banking Regulations [Text Block]	'
	Regulatory Requirements and Subsidiary Dividend Restrictions
	The Company’s subsidiary FCStone, LLC is a commodity futures commission merchant registered with the CFTC servicing customers primarily in grain, energy and food service-related businesses. Pursuant to the rules, regulations, and requirements of the CFTC and other regulatory agencies, FCStone, LLC is required to maintain certain minimum net capital as defined in such rules, regulations, and requirements. Net capital and the related net capital requirement may fluctuate on a daily basis. FCStone, LLC also has restriction on dividends, which restricts the withdrawal of equity capital if the planned withdrawal would reduce net capital, subsequent to haircuts and charges, to an amount less than 120% of the greatest minimum requirement.
	Pursuant to the requirements of the Commodity Exchange Act, funds deposited by customers of FCStone, LLC relating to their trading of futures and options-on-futures on a U.S. commodities exchange must be carried in separate accounts which are designated as segregated customers’ accounts. Pursuant to the requirements of the CFTC, funds deposited by customers of FCStone, LLC relating to their trading of futures and options-on-futures traded on, or subject to the rules of, a foreign board of trade must be carried in separate accounts in an amount sufficient to satisfy all of FCStone LLC’s current obligations to customers trading foreign futures and foreign options on foreign commodity exchanges or boards of trade, which are designated as secured customers’ accounts. See Additional Information of FCStone, LLC Related to Customer Segregated and Secured Funds further below for additional information regarding FCStone, LLC’s calculation of segregated and secured customer funds.
	The Company’s subsidiary INTL FCStone Ltd. is regulated by the Financial Conduct Authority (“FCA”), the regulator of the financial services industry in the United Kingdom, as a Financial Services Firm under part IV of the Financial Services and Markets Act 2000. The regulations impose daily regulatory capital, as well as conduct of business, governance, and other requirements. The conduct of business rules include those that govern the treatment of client money and other assets which under certain circumstances for certain classes of client must be segregated from the firm’s own assets.
	The Company’s subsidiary INTL Global Currencies Limited is regulated by the FCA as a Payment Institution under the Payment Services Regulations 2009. The regulations impose regulatory capital (reported annually), and conduct of business requirements.
	The Company’s subsidiary INTL FCStone Securities Inc. (“INTL FCStone Securities”) is a registered broker dealer and member of the Financial Industry Regulatory Authority (“FINRA”) and is subject to the SEC Uniform Net Capital Rule 15c3-1. This rule requires the maintenance of minimum net capital, and requires that the ratio of aggregate indebtedness to net capital not exceed 15 to 1. A further requirement is that equity capital may not be withdrawn if this ratio would exceed 10 to 1 after such withdrawal.
	The Company’s subsidiary FCC Investments, Inc. is a registered broker-dealer and a member of FINRA, and is subject to the SEC Uniform Net Capital Rule 15c3-1.
	The Company’s subsidiary FCStone Australia Pty Ltd (“FCStone Australia”) is regulated by the Australian Securities and Investment Commission and is subject to a net tangible asset capital requirement. FCStone Australia is also regulated by New Zealand Clearing Limited, and is subject to a capital adequacy requirement.
	FCStone Commodity Services (Europe), Ltd. is domiciled in Ireland and subject to regulation by the Central Bank of Ireland, and is subject to a net capital requirement.
	INTL FCStone DTVM Ltda. (“INTL FCStone DTVM”) is a registered broker-dealer and regulated by the Brazilian Central Bank and Securities and Exchange Commission of Brazil, and is subject to a capital adequacy requirement.
	All subsidiaries of the Company are in compliance with all of their regulatory requirements as of September 30, 2013, as follows:
	(in millions)				As of September 30, 2013
	Subsidiary	Regulatory Authority		Requirement Type	Actual		Minimum
							Requirement
	FCStone, LLC	CFTC		Net capital	$	106.3	$	66.3
	FCStone, LLC	CFTC		Segregated funds	$	1,693.50	$	1,669.60
	FCStone, LLC	CFTC		Secured funds	$	82.5	$	59.8
	INTL FCStone Ltd	FCA (United Kingdom)		Net capital	$	60.8	$	23.4
	INTL FCStone Ltd	FCA United Kingdom		Segregated funds	$	61.2	$	61.1
	INTL Global Currencies Limited	FCA (United Kingdom)		Net capital	$	11.4	$	1.2
	INTL FCStone Securities Inc.	SEC		Net capital	$	5	$	1
	FCC Investments, Inc.	SEC		Net capital	$	0.3	$	0.3
	FCStone Australia	Australian Securities and Investment Commission		Net capital	$	1.8	$	0.9
	FCStone Australia	New Zealand Clearing Ltd		Capital adequacy	$	11.6	$	4.1
	FCStone Commodity Services (Europe), Ltd	Central Bank of Ireland		Net capital	$	2	$	0.6
	INTL FCStone DTVM Ltda.	Brazilian Central Bank and Securities and Exchange Commission of Brazil		Capital adequacy	$	0.7	$	0.7
	INTL Capital S.A.	Rosario Futures Exchange (Argentina)		Capital adequacy	$	6.3	$	0.1
	INTL Capital S.A.	General Inspector of Justice (Argentina)		Net capital	$	8.5	$	6.4
	INTL Capital S.A.	Superintendent of Securities Markets of Buenos Aires (Argentina)		Net capital	$	4	$	0.3
	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 September 30, 2013, these subsidiaries were in compliance with their local capital adequacy requirements.
	Additional Information of FCStone, LLC Related to Customer Segregated and Secured Funds
	Pursuant to the requirements of the Commodity Exchange Act, funds deposited by customers of FCStone, LLC relating to futures and options-on-futures positions in regulated commodities must be carried in separate accounts which are designated as segregated customers’ accounts. Certain amounts in the accompanying table reflect reclassifications and eliminations required for regulatory filing.
	Funds deposited by customers and other assets, which have been segregated as belonging to the commodity customers as of September 30, 2013 and 2012, are as follows:
	(in millions)	September 30, 2013			September 30, 2012
	Cash, at banks - segregated	$	247.6		$	225.6
	Securities - customer segregated	—			—
	Securities held for customers in lieu of cash, at banks	19.5			47.2
	Deposits with and receivables from:
	Exchange-clearing organizations, including securities, net of omnibus eliminations	1,413.30			1,370.40
	Securities held for customers in lieu of cash	13.1			22.3
	Total customer-segregated funds	1,693.50			1,665.50
	Amount required to be segregated	1,669.60			1,620.50
	Excess funds in segregation	$	23.9		$	45
	Funds deposited by customers and other assets, which are held in separate accounts for customers trading foreign futures and foreign options customers, as of September 30, 2013 and 2012 are as follows:
	(in millions)	September 30, 2013			September 30, 2012
	Cash - secured	$	34.2		$	25.2
	Securities	—			3.3
	Equities with futures commission merchants	27			9.9
	Amounts held by clearing organizations of foreign boards of trade	—			20.8
	Amounts held by members of foreign boards of trade	21.3			30.1
	Total customer-secured funds	82.5			89.3
	Amount required to be secured	59.8			77.6
	Excess secured funds	$	22.7		$	11.7

Commodity_and_Other_Repurchase

Commodity and Other Repurchase Agreements	12 Months Ended
	Sep. 30, 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 the sale/repurchase agreements, whereby the 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 September 30, 2013 and 2012 was $9.2 million and $92.5 million, respectively.
	The obligations outstanding related to commodities sold under repurchase agreements that are recorded in ‘broker-dealers, clearing organizations and counterparties’ as of September 30, 2013 and 2012 were $0.0 million and $37.0 million, respectively. The obligations outstanding related to commodities sold under repurchase agreements that are recorded in ‘lenders under loans’ as of September 30, 2013 and 2012 were $6.0 million and $43.2 million, respectively.

ShareBased_Compensation_Notes

Share-Based Compensation (Notes)	12 Months Ended
	Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [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 consolidated income statements and totaled $9.3 million, $5.9 million and $2.3 million for the fiscal years ended 2013, 2012 and 2011, respectively.
	Stock Option Plans
	The Company sponsors a stock option plan for its directors, officers, employees and consultants. The Company’s Board of Directors approved a new stock option plan (“the 2013 Stock Option Plan”), which was approved by the Company’s shareholders at the 2013 annual meeting, and authorized the Company to issue stock options covering up to 1.0 million shares of the Company’s common stock. As of September 30, 2013, there were 1.0 million shares authorized for future grant under this plan. Awards that expire or are canceled generally become available for issuance again under the plan. The Company settles stock option exercises with newly issued shares of common stock.
	Fair value is estimated at the grant date based on a Black-Scholes-Merton option-pricing model using the following weighted-average assumptions:
		Year Ended September 30,
		2013			2012		2011
	Expected stock price volatility	35	%		57	%	77	%
	Expected dividend yield	—	%		—	%	—	%
	Risk free interest rate	0.37	%		1.53	%	0.72	%
	Average expected life (in years)	2.88			7.86		2.94
	Expected stock price volatility rates are primarily based on the historical volatility. The Company has not paid dividends in the past and does not currently expect to do so in the future. Risk free interest rates are based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected life of the option or award. The average expected life represents the estimated period of time that options or awards granted are expected to be outstanding, based on the Company’s historical share option exercise experience for similar option grants. The weighted average fair value of options issued during fiscal years ended 2013, 2012 and 2011 was $4.21, $13.57 and $11.66, respectively.
	The following is a summary of stock option activity for the year ended September 30, 2013:
		Shares			Number of		Weighted		Weighted				Weighted	Aggregate
		Available for			Options		Average		Average				Average	Intrinsic
		Grant			Outstanding		Exercise Price		Grant Date				Remaining	Value
									Fair Value				Term	($ millions)
													(in years)
	Balances at September 30, 2012	921,412			1,890,634		$	23.36	$	11.11			5.45	$	6
	Additional shares authorized by shareholders	1,000,000
	Termination of 2003 plan	(821,412	)
	Granted	(100,000	)		100,000		$	17.53	$	4.21
	Exercised				(177,246	)	$	8.4	$	5.26
	Forfeited	—			(32,738	)	$	10.35	$	3.88
	Expired	—			(667	)	$	23.49	$	11.58
	Balances at September 30, 2013	1,000,000			1,779,983		$	24.76	$	11.44			4.87	$	4.8
	Exercisable at September 30, 2013				680,820		$	27.47	$	11.04			1.91	$	3.1
	The total compensation cost not yet recognized for non-vested awards of $10.0 million as of September 30, 2013 has a weighted-average period of 5.71 years over which the compensation expense is expected to be recognized. The total intrinsic value of options exercised during fiscal years 2013, 2012 and 2011 was $2.0 million, $3.0 million and $1.6 million, respectively.
	The options outstanding as of September 30, 2013 broken down by exercise price are as follows:
	Exercise Price							Number of Options Outstanding	Weighted Average Exercise Price				Weighted Average Remaining Term
													(in Years)
	$	—		-	$	5		—		n/a			n/a
	$	5		-	$	10		301,875	$	7.02			1.18
	$	10		-	$	15		—		n/a			n/a
	$	15		-	$	20		322,179	$	18.01			2.4
	$	20		-	$	25		126,204	$	23.52			3.1
	$	25		-	$	30		800,000	$	25.91			8.22
	$	30		-	$	35		—		n/a			n/a
	$	35		-	$	40		—		n/a			n/a
	$	40		-	$	45		—		n/a			n/a
	$	45		-	$	50		—		n/a			n/a
	$	50		-	$	55		229,725	$	54.23			2.45
								1,779,983	$	24.76			4.87
	Restricted Stock Plan
	The Company sponsors a restricted stock plan for its directors, officers and employees. On January 31, 2012, the Company’s 2007 restricted stock plan expired. On February 23, 2012, shareholders approved the Company’s 2012 restricted stock plan authorizing up to 1.5 million shares to be issued. As of September 30, 2013, 1,154,862 shares were authorized for future grant under the 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 through September 30, 2013:
		Shares			Number of		Weighted		Weighted		Aggregate
		Available for			Shares		Average		Average		Intrinsic Value
		Grant			Outstanding		Grant Date		Remaining		($ millions)
							Fair Value		Term
									(in years)
	Balances at September 30, 2012	1,420,114			512,124		$	22.09	1.81		$	9.8
	Granted	(268,885	)		268,885		$	17.92
	Vested				(406,901	)	$	20.72
	Forfeited	3,633			(10,470	)	$	22.62
	Balances at September 30, 2013	1,154,862			363,638		$	20.53	1.74		$	7.4
	The total compensation cost not yet recognized of $4.9 million as of September 30, 2013 has a weighted-average period of 1.74 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.
	The Company and an executive of a wholly owned subsidiary mutually agreed to the executive’s retirement from employment as of July 1, 2013. As a result of the executive’s retirement from employment, the Company recorded compensation cost, related to the individual’s restricted stock, of $2.6 million during the fiscal year ended September 30, 2013.

Retirement_Plans

Retirement Plans	12 Months Ended
	Sep. 30, 2013
Compensation and Retirement Disclosure [Abstract]	'
Pension and Other Postretirement Benefits Disclosure [Text Block]	'
	Retirement Plans
	Defined Benefit Retirement Plans
	As a result of its acquisition of FCStone on September 30, 2009, the Company has a qualified and a nonqualified noncontributory retirement plan, which are defined benefit plans that cover certain employees. Prior to acquisition, the plans were closed to new employees, and amended to freeze all future benefit accruals, therefore no additional benefits accrue for active participants under the plans.
	The following table presents changes in, and components of, the Company’s net liability for retirement costs as of and for the years ended September 30, 2013, 2012 and 2011, based on measurement dates of September 30, 2013, 2012 and 2011, respectively:
	(in millions)	September 30, 2013			September 30, 2012			September 30, 2011
	Changes in benefit obligation:
	Benefit obligation, beginning of year	$	42.8		$	39		$	37.6
	Interest cost	1.5			1.8			1.9
	Actuarial loss	(2.6		)	5.8			2.6
	Benefits paid	(4.2		)	(3.8		)	(3.1		)
	Benefit obligation, end of year	37.5			42.8			39
	Changes in plan assets:
	Fair value, beginning of year	26.5			24.2			24.2
	Actual return	3.7			4.6			(0.4		)
	Employer contribution	2.9			1.5			3.5
	Benefits paid	(4.2		)	(3.8		)	(3.1		)
	Fair value, end of year	28.9			26.5			24.2
	Funded status	$	(8.6	)	$	(16.3	)	$	(14.8	)
	The Company is required to recognize the funded status of its defined benefit pension plans measured as the difference between plan assets at fair value and the projected benefit obligation on the consolidated balance sheets as of September 30, 2013 and 2012, and to recognize changes in the funded status, that arise during the periods but are not recognized as components of net periodic pension cost, within accumulated other comprehensive loss, net of tax. Amounts recognized in the consolidated balance sheets consist of $0.5 million and $0.1 million included in ‘other assets’ as of September 30, 2013 and 2012, respectively, and $9.1 million and $16.4 million included in ‘accounts payable and other accrued liabilities’ as of September 30, 2013 and 2012, respectively.
	Accumulated other comprehensive loss, net of tax, includes amounts for actuarial losses in the amount of $2.9 million and $6.2 million as of September 30, 2013 and 2012, respectively. The estimated net loss for the defined benefit pension plans that will be amortized from accumulated other comprehensive loss into net periodic pension cost during fiscal 2014 is $0.2 million.
	The following table displays the Company’s defined benefit plans that have accumulated benefit obligations and projected benefit obligations in excess of the fair value of plans assets (underfunded ABO) as of September 30, 2013 and 2012:
	(in millions)	September 30, 2013			September 30, 2012
	Accumulated benefit obligations	$	37.5		$	42.8
	Projected benefit obligations	$	37.5		$	42.8
	Plan assets	$	28.9		$	26.5
	The defined benefit obligations were based upon annual measurement dates of September 30, 2013 and 2012. The following weighted-average assumptions were used to determine benefit obligations in the accompanying consolidated balance sheets as of September 30, 2013 and 2012:
		September 30, 2013		September 30, 2012
	Weighted average assumptions:
	Discount rate	4.60%		3.80%
	Expected return on assets	7.00%		7.00%
	The following weighted-average assumptions were used to determine net periodic pension cost for the years ended September 30, 2013, 2012 and 2011:
		Year Ended September 30,
		2013		2012	2011
	Weighted average assumptions:
	Discount rate	3.80%		4.80%	5.30%
	Expected return on assets	7.00%		7.30%	7.30%
	To account for the defined benefit pension plans in accordance with the guidance in the Compensation – Retirement Benefits Topic of the ASC the Company makes two main determinations at the end of each fiscal year. These determinations are reviewed annually and updated as necessary, but nevertheless, are subjective and may vary from actual results.
	First, the Company must determine the actuarial assumption for the discount rate used to reflect the time value of money in the calculation of the projected benefit obligations for the end of the current fiscal year and to determine the net periodic pension cost for the subsequent fiscal year. The objective of the discount rate assumption is to reflect the interest rate at which pension benefits could be effectively settled. In making this determination, the Company considers the timing and amount of benefits that would be available under the plans. The discount rates as of September 30, 2013, 2012 and 2011 were based on a model portfolio of high-quality fixed-income debt instruments with durations that are consistent with the expected cash flows of the benefit obligations.
	Second, the Company must determine the expected long-term rate of return on assets assumption that is used to determine the expected return on plan assets component of the net periodic pension cost for the subsequent period. The expected long-term rate of return on asset assumption was determined, with the assistance of the Company’s investment consultants, based on a variety of factors. These factors include, but are not limited to, the plan’s asset allocations, a review of historical capital market performance, historical plan performance, current market factors such as inflation and interest rates, and a forecast of expected future asset returns. The Company reviews this long-term assumption on an annual basis.
	As a result of the defined benefit plans having a frozen status, no additional benefits will be accrued for active participants under the plan, and accordingly no assumption will be made for the rate of increase in compensation levels in the future.
	The components of net periodic pension cost recognized in the consolidated income statements for the years ended September 30, 2013, 2012 and 2011 were as follows:
		Year Ended September 30,
	(in millions)	2013			2012			2011
	Interest cost	$	1.5		$	1.8		$	1.9
	Less expected return on assets	(1.8		)	(1.7		)	(1.7		)
	Net amortization and deferral	0.8			0.4			—
	Net periodic pension cost	$	0.5		$	0.5		$	0.2
	Other changes in plan assets and benefit obligations recognized in other comprehensive income for the years ended September 30, 2013 and 2012 were as follows:
		Year Ended September 30,
	(in millions)	2013			2012
	Net (gain) loss	$	(4.6	)	$	2.9
	Amortization of loss	(0.8		)	(0.4		)
	Total recognized in other comprehensive income	(5.4		)	2.5
	Total recognized in net periodic benefit cost and other comprehensive income	$	(4.9	)	$	3
	Plan Assets
	The following table sets forth the actual asset allocation as of September 30, 2013 and 2012, and the target asset allocation for the Company’s plan assets:
		September 30, 2013		September 30, 2012	Target Asset Allocation
	Equity securities	68%		66%	70%
	Debt securities	32%		34%	30%
	Total	100%		100%
	The long-term goal for equity exposure and for fixed income exposure is presented above. The exact allocation at any point in time is at the discretion of the investment manager, but should recognize the need to satisfy both the volatility and the rate of return objectives for equity exposure and satisfy the objective of preserving capital for the fixed income exposure.
	The investment philosophy of the Company’s pension plans reflect that over the long-term, the risk of owning equities has been and should continue to be rewarded with a greater return than that available from fixed income investments. The primary objective is for the plan to achieve a rate of return sufficient to fully fund the pension obligation without assuming undue risk.
	Investments in the Company’s pension plans include debt and equity securities. The fair value of plan assets is based upon the fair value of the underlying investments, which include cash equivalents, common stock, U.S. government securities and federal agency obligations, municipal and corporate bonds, and equity funds. Cash equivalents consist of short-term money market funds that are stated at cost, which approximates fair value. The shares of common stock, U.S. government securities and federal agency obligations, municipal and corporate bonds are stated at estimated fair value based upon quoted market prices, if available, or dealer quotes. The equity funds are investment vehicles valued using the net asset value (“NAV”) provided by the administrator of the fund. The NAV is based on the underlying assets owned by the fund, minus its liabilities, and then divided by the number of shares outstanding.
The methods described above may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. Furthermore, while the Company believes the valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement at the reporting date.
Equity securities did not include any INTL FCStone Inc. common stock as of September 30, 2013 and 2012, respectively.
The following tables summarize the Company’s pension assets, excluding cash held in the plan, by major category of plan assets measured at fair value on a recurring basis (at least annually) as of September 30, 2013 and 2012. For additional information and a detailed description of each level within the fair value hierarchy, see Note 4.
	September 30, 2013
(in millions)	Level 1			Level 2			Level 3			Total
Assets:
Cash equivalents	$	—		$	0.5		$	—		$	0.5
Fixed income:
Government and agencies	—			0.6			—			0.6
Collective funds:
Fixed income	—			8.1			—			8.1
Equities	—			18.7			—			18.7
Real estate	—			1			—			1
Total	$	—		$	28.9		$	—		$	28.9
	September 30, 2012
(in millions)	Level 1			Level 2			Level 3			Total
Assets:
Cash equivalents	$	—		$	0.4		$	—		$	0.4
Fixed income:
Government and agencies	—			0.8			—			0.8
Collective funds:
Fixed income	—			7.7			—			7.7
Equities	—			16.6			—			16.6
Real estate	—			1			—			1
Total	$	—		$	26.5		$	—		$	26.5
Cash equivalents are mostly comprised of short-term money market instruments and the valuation is based on inputs derived from observable market data of related assets.
Fixed Income: These securities primarily include debt issued by the U.S. Department of Treasury and securities issued or backed by U.S. government sponsored entities and municipal bonds. These investments are valued utilizing a market approach that includes various valuation techniques and sources such as, broker quotes in active and non-active markets, benchmark yields and securities, reported trades, issuer spreads, and/or other applicable reference data and are generally classified within Level 2.
Mutual Funds: Mutual funds held by the Company’s plans are primarily invested in mutual funds with underlying common stock investments. The fair value of these investments is based on the net asset value (“NAV”) of the units held in the respective fund which are determined by obtaining quoted prices on nationally recognized securities exchanges.
Collective Funds: These collective investment funds are unregistered investment vehicles that invest in portfolios of stock, bonds, or other securities. The fair value of these investments is based on the NAV of the units held in the respective funds. As no redemption restrictions or other features are noted that require adjustment to NAV. These funds are classified as Level 2 investments.
The Company expects to contribute $2.5 million to the pension plans during fiscal 2014, which represents the minimum funding requirement. However, the Company is currently determining what voluntary pension plan contributions, if any, will be made in fiscal 2014.
The following benefit payments, which reflect expected future service, are expected to be paid:
(in millions)
Year ending September 30,
2014	$	3.6
2015	3.3
2016	3.2
2017	2.9
2018	1.9
2019 - 2023	9.5
	$	24.4
Defined Contribution Retirement Plans
U.K. based employees of INTL FCStone are eligible to participate in a defined contribution pension plan. The Company contributes double the employee’s contribution up to 10% of total base salary for this plan. For this plan, employees are 100% vested in both the employee and employer contributions at all times.
The Company offers participation in the INTL FCStone Inc. 401(k) Plan (“401(k) Plan”), a defined contribution plan providing retirement benefits, to all domestic employees who have reached 21 years of age, and provided four months of service to the Company. Employees may contribute from 1% to 80% of their annual compensation to the 401(k) Plan, limited to a maximum annual amount as set periodically by the Internal Revenue Service. The Company makes matching contributions to the 401(k) Plan in an amount equal to 62.5% of each participant’s eligible elective deferral contribution to the 401(k) Plan, up to 8%. Matching contributions vest, by participant, based on the following years of service schedule: less than two years – none, two to three years – 20%, three to four years – 40%, four to five years – 60%, and greater than five years – 100%.
For fiscal years ended 2013, 2012 and 2011, the Company’s contribution to these defined contribution plans were $4.0 million, $3.7 million and $2.8 million, respectively.

Other_Expenses_Notes

Other Expenses (Notes)	12 Months Ended
	Sep. 30, 2013
Other Expenses [Abstract]	'
Other Expenses [Text Block]	'
	Other Expenses
	Other expenses for the years ended September 30, 2013, 2012 and 2011 are comprised of the following:
		Year Ended September 30,
	(in millions)	2013		2012		2011
	Contingent consideration, net(1)	3		2.9		4.7
	Insurance	1.8		1.7		1.5
	Advertising, meetings and conferences	2.3		2.5		1.8
	Non-trading hardware and software maintenance and software licensing	2.7		2.2		2.8
	Office supplies and printing	1.2		1.3		1.1
	Other clearing related expenses	1.6		1.7		1.8
	Other non-income taxes	3.8		4		2.8
	Other	6.8		5.3		4.9
	Total other expenses	$	23.2	$	21.6	$	21.4
	(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 4) and additional purchase price, based on achieving specific conditions and earnings targets, relating to FCStone, LLC’s previous acquisitions of Downes O’Neill, LLC (“Downes O’Neill”) and Globecot, Inc. (“Globecot”). When the Downes O’Neill and Globecot acquisitions occurred, they were recorded in accordance with SFAS No. 141, Business Combinations (“SFAS 141”). As a result of the FCStone transaction on September 30, 2009, these contingent purchase price amounts were considered pre-acquisition contingencies, which were not reasonably estimable during the merger allocation period following the FCStone transaction. In accordance with SFAS 141, adjustments to pre-acquisition contingencies, made after the end of the allocation period, are included in earnings in the current period. The final pre-acquisition contingency expense was recorded during fiscal year 2013 and there are no further contingent payments relating to the Downes O’Neill or Globecot acquisitions.

Income_Taxes_Notes

Income Taxes (Notes)	12 Months Ended
	Sep. 30, 2013
Income Taxes [Abstract]	'
Income Tax Disclosure [Text Block]	'
	Income Taxes
	Income tax expense (benefit) for the years ended September 30, 2013, 2012 and 2011 was allocated as follows:
		Year Ended September 30,
	(in millions)	2013				2012				2011
						(As Restated)				(As Restated)
	Income tax expense attributable to income from continuing operations	$	3.3			$	3.1			$	20.9
	Income tax expense attributable to loss from discontinued operations	—				—				0.1
	Taxes allocated to stockholders’ equity, related to unrealized gains (losses) on available-for-sale securities	(1.6		)		2.2				(0.3		)
	Taxes allocated to stockholders’ equity, related to pension liabilities	1.8				(1.0		)		(1.7		)
	Taxes allocated to stockholders’ equity, related to unrealized loss on derivatives	—				—				0.6
	Taxes allocated to additional paid-in capital, related to share-based compensation	—				(0.2		)		—
	Total income tax expense	$	3.5			$	4.1			$	19.6
	The components of the provision for income taxes attributable to income from continuing operations were as follows:
		Year Ended September 30,
	(in millions)	2013				2012				2011
						(As Restated)				(As Restated)
	Current taxes:
	U.S. Federal	$	(1.2	)		$	(6.9	)		$	7.6
	U.S. State and local	(1.3		)		0.4				1.6
	International	13.5				10.1				9.9
	Total current taxes	11				3.6				19.1
	Deferred taxes	(7.7		)		(0.5		)		1.8
	Income tax expense	$	3.3			$	3.1			$	20.9
	U.S. and international components of (loss) income from continuing operations, before income taxes, was as follows:
		Year Ended September 30,
	(in millions)	2013				2012				2011
						(As Restated)				(As Restated)
	U.S.	$	(21.7	)		$	(17.2	)		$	23.2
	International	44.3				33				32.2
	Income from continuing operations, before tax	$	22.6			$	15.8			$	55.4
	Items accounting for the difference between income taxes computed at the federal statutory rate and the provision for income taxes were as follows:
		Year Ended September 30,
		2013			2012			2011
					(As Restated)			(As Restated)
	Federal statutory rate effect of:	35	%		35	%		35	%
	U.S. State and local income taxes	0.8	%		(2.0	)%		0.8	%
	Foreign earnings taxed at lower rates	(20.1	)%		(20.4	)%		(3.1	)%
	Change in foreign valuation allowance	(0.2	)%		2.2	%		0.7	%
	Change in state valuation allowance	(7.6	)%		(0.2	)%		1	%
	Tax impact of U.S. State and local rate change	(2.4	)%		—	%		1.2	%
	Uncertain tax positions	(0.3	)%		(1.5	)%		1.5	%
	Non-deductible meals and entertainment	1.3	%		2.7	%		—	%
	Foreign permanent items	4.3	%		6	%		—	%
	Other reconciling items	3.9	%		(4.2	)%		0.6	%
	Penalties	2.4	%		—	%		—	%
	Audit settlements	(1.7	)%		—	%		—	%
	Effective rate	15.4	%		17.6	%		37.7	%
	The components of deferred income tax assets and liabilities were as follows:
	(in millions)	September 30, 2013				September 30, 2012
						(As Restated)
	Deferred tax assets:
	Share-based compensation	$	2.7			$	2.5
	Pension liability	3.4				6.1
	Deferred compensation	2.3				3.2
	Foreign net operating loss carryforwards	1.9				2
	U.S. State and local net operating loss carryforwards	4.9				4.9
	U.S. Federal net operating loss carryforwards	7.3				—
	Intangible assets	6.9				6.1
	Capital loss carryforwards	0.7				1.1
	Bad debt reserve	0.2				0.1
	Foreign tax credit	0.1				0.3
	Other compensation	1.6				4.5
	Other	1.4				1.2
Total gross deferred tax assets	33.4				32
Less valuation allowance	(2.3		)		(4.1		)
Deferred tax assets	31.1				27.9
Deferred income tax liabilities:
Unrealized gain on securities	1.3				3.1
Prepaid expenses	0.9				1.1
Fixed assets	3.4				3.8
Deferred income tax liabilities	5.6				8
Net deferred tax assets	$	25.5			$	19.9
Deferred income tax balances reflect the effects of temporary differences between the carrying amounts of assets and liabilities and their tax bases and are stated at enacted tax rates expected to be in effect when taxes are actually paid or recovered.
As of September 30, 2013 and 2012, the Company has net operating loss carryforwards for U.S. federal, state, and local and foreign income tax purposes of $11.8 million and $2.8 million, net of valuation allowances, respectively, which are available to offset future taxable income in these jurisdications. The U.S. federal net operating loss carryforward of $7.3 million expires in 2033. The state and local net operating loss carryforwards of $4.5 million, net of valuation allowance, expire in tax years ranging from 2020 through 2033.
The valuation allowance for deferred tax assets as of 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 September 30, 2013 and 2012 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 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 16 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.
The total amount of undistributed earnings in the Company’s foreign subsidiaries, for income tax purposes, was $123.1 million and $93.8 million as of September 30, 2013 and 2012, respectively. It is the Company’s current intention to reinvest undistributed earnings of its foreign subsidiaries in the foreign jurisdictions, resulting in the indefinite postponement of the remittance of those earnings. Accordingly, no provision has been made for foreign withholding taxes or U.S. federal income taxes which may become payable if undistributed earnings of foreign subsidiaries were paid as dividends to the Company.
The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authority, based upon the technical merits of the position. The tax benefit recognized in the consolidated financial statements from such a position is measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement.
A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
	Year Ended September 30,
(in millions)	2013				2012				2011
Balance, beginning of year	$	0.5			$	0.9			$	—
Gross increases for tax positions related to current year	0.1				—				—
Gross increases for tax positions related to prior years	—				—				0.9
Gross decreases for tax positions of prior years	(0.2		)		(0.1		)		—
Settlements	(0.2		)		(0.1		)		—
Lapse of statute of limitations	(0.1		)		(0.2		)		—
Balance, end of year	$	0.1			$	0.5			$	0.9
Included in the balance of uncertain tax benefits as of September 30, 2013, is $0.1 million of tax benefits that, if recognized, would affect the effective tax rate. While it is expected that the amount of unrecognized tax benefits will change in the next twelve months, the Company does not expect this change to have a material impact on the results of operations or the financial position of the Company.
Accrued interest and penalties are included in the related tax liability line in the consolidated balance sheets. Accrued interest, net of federal benefit, and penalties included in the consolidated balance sheets as of September 30, 2013 and 2012 was $0.0 million and $0.2 million, respectively.
The Company recognizes accrued interest and penalties related to income taxes as a component of income tax expense. During 2013, 2012 and 2011, the amount of interest, net of federal benefit, and penalties recognized as a component of income tax expense was $(0.2) million, $0.3 million and $0.2 million, respectively.
The Company and its subsidiaries file income tax returns with the U.S. federal jurisdiction and various U.S. state and local 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. There are no examinations taking place in foreign jurisdictions.

Acquisitions_and_Disposals_Not

Acquisitions and Disposals (Notes)	12 Months Ended
	Sep. 30, 2013
Business Combinations [Abstract]	'
Business Combination Disclosure [Text Block]	'
	Acquisitions and Disposals
	Acquisitions in Fiscal 2013
	The Company’s consolidated financial statements include the operating results of the acquired businesses from the dates of acquisition. The total amount of goodwill and intangible assets, in connection with these acquisitions, that is expected to be deductible for tax purposes is $5.6 million as of September 30, 2013.
	First American Capital and Trading Corp.
	On May 3, 2013, the Company reached an agreement in which First American Capital and Trading Corp. (“FACT”), has agreed to transfer its customer accounts to INTL FCStone Inc.’s broker-dealer subsidiary, INTL FCStone Securities Inc. Completion of this transaction is subject to certain conditions, including regulatory approval. FACT provides correspondent clearing services to institutional customers directly and through a global network of partners. FACT services a wide range of customers, including broker-dealers, investment advisors, and fund managers. The Company completed this transaction in the first quarter of fiscal 2014.
	Tradewire
	On December 12, 2012, the Company finalized an agreement to acquire certain institutional accounts from Tradewire Securities, LLC (“Tradewire Securities”), a Miami-based securities broker-dealer servicing customers throughout Latin America and a wholly owned subsidiary of Tradewire Group Ltd. These accounts were transferred to INTL FCStone Inc.’s broker-dealer subsidiary, INTL FCStone Securities. As part of the transaction, the Company hired more than 20 professional staff from Tradewire Securities’ securities broker-dealer business based in Miami, Florida. These professionals provide global brokerage services to a wide range of customers, including hedge funds, pension funds, broker-dealers and banks located in Latin America, the Caribbean, North America and Europe.
	The consideration to be paid for the acquisition of institutional accounts from Tradewire Securities consists of three annual contingent payments and a final contingent payment and the original estimated present value was estimated to be $5.6 million as of the acquisition date. The purchase price for the acquisition is not expected to be material to the consolidated financial statements. The present value of the estimated total purchase price, including contingent consideration, is $6.3 million (see Note 12). The Company obtained a third-party valuation of the intangible assets and contingent liabilities, and allocated the purchase costs among identified intangible assets with determinable useful lives and goodwill. The goodwill and intangible assets recognized in this transaction of $2.8 million and $2.8 million, respectively, were assigned to the Securities segment.
	Disposals in Fiscal 2013
	Gletir Agente De Valores S.A.
	On February 28, 2013, the Company, through its subsidiaries INTL Netherlands B.V. and Gainvest Asset Management Ltda, entered into an agreement to sell all of its ownership interest in another subsidiary, Gletir Agente De Valores S.A. (“Gletir Agente”), to Gletir Financial Corp (the “Purchaser”). The Company sold the capital stock of Gletir Agente for $0.8 million. Gletir Agente had net assets of $0.6 million, which included $0.1 million of AOCI related to foreign currency translation, included in the consolidated balance sheet of the Company, at the time of the sale. The gain resulting from the sale price less the carrying amount of the net assets and the gain from the AOCI balance were recorded as components of other income on the consolidated income statement for the fiscal year ended ended September 30, 2013.
	Exit of Physical Base Metals Business
	During the quarter ended March 31, 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/or orderly liquidation of current open positions. During the fiscal year ended September 30, 2013, 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 performance of the physical base metals activities resulted in pre-tax income of $1.4 million during the fiscal year ending September 30, 2013, including $1.9 million in contract termination costs incurred in the aforementioned sale. The Company believes the exit of the physical base metals business will be completed by the end of fiscal 2014. The physical base metals business is included in the C&RM Segment. The Company will continue 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 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 consolidated financial statements.
	Acquisitions in Fiscal 2012
	During fiscal 2012, the Company acquired three businesses (Coffee Network, TRX Futures Limited and Aporte DTVM) and certain assets of the Metals Division of MF Global UK Limited, which were not considered significant on an individual or aggregate basis. The Company’s consolidated financial statements include the operating results of the acquired businesses from the dates of acquisition.
	These acquisitions resulted in the recognition of goodwill and intangible assets that is expected to be deductible for tax purposes of $0.7 million.
	Coffee Network
	In November 2011, the Company entered into an agreement to acquire 100% of the ownership interests in Coffee Network LLC (“Coffee Network”), an online news and analysis portal for the global coffee industry. Coffee Network provides up-to-the-minute news and in-depth analysis to subscribers around the globe from a network of correspondents and commodity analysts located in key coffee producing and consuming regions. These services provide a unique information solution to subscribers and a competitive advantage in today’s information-driven marketplace.
	The purchase price for the Coffee Network acquisition consists of an initial payment of $0.2 million, three additional annual contingent payments and a final contingent payment. See Note 12 for discussion of the contingent payments. The present value of the estimated total purchase price, including contingent consideration, is less than $0.3 million. The intangible assets recognized in this transaction were assigned to the C&RM segment. Purchase costs allocated to intangible assets with determinable useful lives are $0.2 million, which are being amortized over the remaining useful lives of the assets, and include customer relationships, websites and non-compete agreements (approximate two-year weighted-average useful life).
	MF Metals Team
	On November 25, 2011, INTL FCStone Ltd. Ltd, the Company’s wholly owned subsidiary in the United Kingdom (“UK”), arranged with the administrator of MF Global’s UK operations to acquire certain assets of the Metals Division of MF Global UK Limited (in special administration). As part of the arrangement, the Company received an assignment of customer accounts and customer account documentation. Additionally, as part of the transaction, the Company hired more than 50 professionals from MF Global’s metals trading business based in London. This business serves institutional investors and financial services firms in the Americas, Europe and the Asia-Pacific region. The Company has allocated equity capital to integrate these brokers and their customers into the Company’s operations, through a combination of increased regulatory capital to support the accounts of these customers and increased compensation and related personnel costs for the brokers. The amount of the required capital depends upon the activity in and balances of the customer accounts.
	The purchase price of the acquisition of certain assets from MF Global was $1.0 million. There was no contingent consideration associated with this transaction. The intangible assets recognized in this transaction were assigned to the C&RM segment. Purchase costs allocated to intangible assets with determinable useful lives are $0.5 million, which are being amortized over the remaining useful lives of the assets, and include customer relationships (approximate three-year weighted-average useful life).
	TRX Futures Limited
	On April 30, 2012, the Company’s wholly owned subsidiary in the UK, INTL Holding (UK) Limited, acquired 100% of the outstanding shares of TRX Futures Limited (“TRX”) from Neumann Gruppe GmbH. TRX is a London-based niche clearing firm for commercial coffee and cocoa customers, as well as energy and financial products. The purchase price was equal to the tangible net asset value of TRX, which was approximately $12.9 million. There are no additional payments remaining for this acquisition. The goodwill recognized in this transaction was assigned to the C&RM segment. Purchase costs allocated to goodwill of $0.3 million was calculated as the excess of the fair value of the consideration transferred over the fair value of the identified net assets acquired and liabilities assumed, and is expected to be deductible for tax purposes.
	Aporte DTVM
	In February 2012, the Company’s subsidiaries, INTL Participacoes LTDA and FCStone do Brasil, acquired 100% of the shares of Aporte DTVM. Following the acquisition, Aporte DTVM was renamed INTL FCStone DTVM Ltda. INTL FCStone DTVM is based in Brazil and is a broker-dealer regulated by the Central Bank of Brazil. The purchase price for the acquisition of the shares of Aporte DTVM was $1.5 million. There are no additional payments remaining for this acquisition. The goodwill recognized in this transaction was assigned to the C&RM segment. Purchase costs allocated to goodwill of $0.8 million was calculated as the excess of the fair value of the consideration transferred over the fair value of the identified net assets acquired and liabilities assumed, and is expected to be deductible for tax purposes.
	Acquisitions in Fiscal 2011
	During fiscal 2011, the Company acquired two businesses, Hencorp Futures and Ambrian Commodities Limited, and certain assets from Hudson Capital Energy, LLC, which were not considered significant on an individual or aggregate basis. The Company’s consolidated financial statements include the operating results of the two businesses and certain purchased assets from the dates of acquisition.
	These acquisitions resulted in the recognition of goodwill and intangible assets that is expected to be deductible for tax purposes of $4.9 million.
	Hencorp Futures
	In October, 2010, the Company acquired all of the ownership interests in Hencorp Futures, the commodity futures operation of Miami-based Hencorp Group. Hencorp Futures specializes in the development and execution of risk-management programs designed to hedge price volatility in a number of widely traded commodities, including coffee, sugar, cocoa, grains and energy products. The transaction will enable the Company to round out its portfolio of commodity risk management services to include a more robust capability in soft commodities, especially coffee, where Hencorp Futures has established a substantial presence and reputation globally, and especially in Central and South America.
	The purchase price of the Hencorp Futures acquisition consisted of an initial payment of $2.3 million, two payments totaling $1.4 million and representing the adjusted tangible equity of Hencorp Futures as of September 30, 2011, payments of $0.3 million based on the adjusted pre-tax net earnings of Hencorp Futures for the fiscal year ended September 30, 2011 and 2012, respectively, two additional annual contingent payments and a final contingent payment. See Note 12 for discussion of the contingent payments. The present value of the estimated total purchase price, including contingent consideration, is $7.5 million.
	The Company obtained a third-party valuation of the intangible assets and contingent liabilities, and allocated the purchase costs among tangible assets, identified intangible assets with determinable useful lives, intangible assets with indefinite lives and goodwill. The intangible assets and goodwill recognized in this transaction were assigned to the C&RM segment. Purchase costs allocated to intangible assets with determinable useful lives are $1.7 million, which are being amortized over the remaining useful lives of the assets, and include customer relationships of $1.3 million (twenty-year weighted-average useful life) and non-compete agreements of $0.4 million (two-year weighted-average useful life). Purchase costs allocated to intangible assets with indefinite lives are $0.8 million, and relate to a trade name. See discussion in Note 10 for discussion of the impairment of the Hencorp Futures trade name during the fiscal year ended September 30, 2012. Goodwill of $2.1 million was calculated as the excess of the fair value of the consideration transferred over the fair value of the identified net assets acquired and liabilities assumed, and is expected to be deductible for tax purposes. During 2012, Hencorp Futures was reorganized as a division of FCStone, LLC.
	Certain Assets Purchased from Hudson Capital Energy, LLC
	In April 2011, the Company acquired certain assets from Hudson Capital Energy LLC (“HCEnergy”), a New York-based energy risk-management firm. The transaction enables the Company’s energy risk management services to include a more robust capability in crude oil and refined products. HCEnergy is a specialist in exchange cleared options, swaps and futures, and has grown its business to include hedging and trading professionals across the spectrum of global petroleum products.
	The purchase price of the acquisition of certain assets from HCEnergy consisted of the aggregate net asset value of certain commodity futures brokerage accounts and certain proprietary software, totaling $1.0 million. There was no contingent consideration associated with this transaction.
	The Company has made an allocation of the purchase costs among tangible assets. There were no intangible assets or goodwill recognized in this transaction.
	Ambrian Commodities Limited
	In August 2011, the Company’s wholly owned subsidiary in the United Kingdom, INTL Global Currencies Limited, acquired the issued share capital of Ambrian Commodities Limited (“Ambrian”), the London Metals Exchange brokerage subsidiary of Ambrian Capital Plc. Ambrian was subsequently renamed INTL FCStone Ltd. (“INTL FCStone Europe”). INTL FCStone Europe, a non-clearing LME member, specializes in the development and execution of risk-management programs designed to hedge price fluctuations in base metals for a wide variety of producers, manufacturers and fabricators. INTL FCStone Europe has a niche focus on smaller industrial clients, including lead recyclers, brass producers, zinc galvanizers, metal refineries and copper foil producers that use LME futures and options for hedging raw material costs or output prices.
	At closing, the Company paid $7.1 million, representing the net asset value of Ambrian less certain intercompany balances due to Ambrian from its affiliates. There was no contingent consideration associated with this transaction. The Company has allocated the purchase costs among tangible assets. There were no intangible assets or goodwill recognized in this transaction.

Discontinued_Operations

Discontinued Operations	12 Months Ended
	Sep. 30, 2013
Discontinued Operations and Disposal Groups [Abstract]	'
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	'
	Discontinued Operations
	On June 10, 2010, the board of directors of Agora, LLC (“Agora”) agreed to discontinue the operations of the entity, at which time the Company held a 15% noncontrolling ownership interest in Agora. During 2011, the Company recognized a gain of $0.2 million, net of taxes, related to the final liquidation of Agora in discontinued operations. The results of Agora were previously included in the Other segment.

Quarterly_Financial_Informatio

Quarterly Financial Information (Unaudited)	12 Months Ended
	Sep. 30, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Quarterly Financial Information [Text Block]	'
	Quarterly Financial Information (Unaudited)
	The impact of the immaterial correction of the reconciliation errors and errors relating to certain intercompany physical sales, as previously discussed in Note 2, to the fiscal 2013 quarterly information is as follows:
		For the 2013 Fiscal Quarter Ended
	(in millions, except per share amounts)	September 30				30-Jun					31-Mar							31-Dec
						As Reported		As Revised			As Reported			As Revised				As Reported		As Revised
	Total revenues	$	9,030.40			$	11,039.50	$	9,996.60		$	13,113.10		$	12,188.50			$	12,719.50	$	12,552.80
	Cost of sales of physical commodities	8,917.80				10,917.40		9,873.80			12,995.80			12,071.20				12,593.80		12,427.10
	Operating revenues	112.6				122.1		122.8			117.3			117.3				125.7		125.7
	Transaction-based clearing expenses	28				28.9		28.9			28.6			28.6				24.6		24.6
	Introducing broker commissions	11.5				11		11			9.6			9.6				8.4		8.4
	Interest expense	2.9				3.2		3.2			2.9			2.9				3.5		3.5
	Net operating revenues	70.2				79		79.7			76.2			76.2				89.2		89.2
	Compensation and other expenses	72.7				74.9		74.8			74.8			74.8				70.4		70.4
	(Loss) income before tax	(2.5		)		4.1		4.9			1.4			1.4				18.8		18.8
	Income tax (benefit) expense	(3.7		)		1.3		1.6			(0.1		)	(0.1		)		5.5		5.5
	Net income	$	1.2			$	2.8	$	3.3		$	1.5		$	1.5			$	13.3	$	13.3
	Net basic earnings per share	$	0.05			$	0.15	$	0.18		$	0.08		$	0.08			$	0.7	$	0.7
	Net diluted earnings per share	$	0.04			$	0.15	$	0.17		$	0.08		$	0.08			$	0.68	$	0.68
	The impact of the restatement for the correction of the reconciliation errors and the immaterial correction of errors relating to certain intercompany physical sales, as previously discussed in Note 2, to the fiscal 2012 quarterly information is as follows:
		For the 2012 Fiscal Quarter Ended
	(in millions, except per share amounts)	30-Sep						30-Jun						31-Mar						31-Dec
		As Reported			As Restated			As Reported		As Restated				As Reported			As Restated			As Reported			As Restated
	Total revenues	$	17,668.10		$	17,369.10		$	17,351.10	$	17,192.90			$	16,951.00		$	16,808.00		$	17,290.40		$	16,589.30
	Cost of sales of physical commodities	17,550.10			17,251.20			17,227.30		17,071.40				16,831.40			16,689.50			17,194.10			16,493.00
	Operating revenues	118			117.9			123.8		121.5				119.6			118.5			96.3			96.3
	Transaction-based clearing expenses	26			26			30.3		30.3				26.9			26.9			22.2			22.2
	Introducing broker commissions	9.3			9.3			7.9		7.9				8			8			5.8			5.8
	Interest expense	3.3			3.3			2.6		2.6				3.6			3.6			2.1			2.1
	Net operating revenues	79.4			79.3			83		80.7				81.1			80			66.2			66.2
	Compensation and other expenses	68.9			68.9			77.1		77.1				77.5			77.5			66.9			66.9
	Income from continuing operations, before tax	10.5			10.4			5.9		3.6				3.6			2.5			(0.7		)	(0.7		)
	Income tax expense (benefit)	2.2			2.1			1.2		0.4				1.2			0.8			(0.2		)	(0.2		)
	Income (loss) from continuing operations	8.3			8.3			4.7		3.2				2.4			1.7			(0.5		)	(0.5		)
	Add: Net loss attributable to noncontrolling interests	—			—			—		—				—			—			0.1			0.1
	Net income (loss) attributable to INTL FCStone Inc. common stockholders	$	8.3		$	8.3		$	4.7	$	3.2			$	2.4		$	1.7		$	(0.4	)	$	(0.4	)
	Net basic earnings (loss) per share	$	0.44		$	0.44		$	0.24	$	0.16			$	0.13		$	0.09		$	(0.02	)	$	(0.02	)
	Net diluted earnings (loss) per share	$	0.42		$	0.42		$	0.23	$	0.15			$	0.12		$	0.09		$	(0.02	)	$	(0.02	)

Segment_and_Geographic_Informa

Segment and Geographic Information (Notes)	12 Months Ended
	Sep. 30, 2013
Segment Analysis [Abstract]	'
Segment Reporting Disclosure [Text Block]	'
	Segment and Geographic Information
	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 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 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 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 businesses and net revenues for all other businesses. 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 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 expenses and related 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, travel and 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:
		Year Ended September 30,
	(in millions)	2013		2012			2011
				(As Restated)			(As Restated)
	Total revenues:
	Commodity and Risk Management Services	$	43,218.20	$	67,627.00		$	72,667.80
	Foreign Exchange	66.9		62.6			59.3
	Securities	61.1		39.9			30.5
	Clearing and Execution Services	100.8		93.8			66.1
	Other	314.1		136.2			67.2
	Corporate unallocated	7.2		(0.2		)	0.4
	Total	$	43,768.30	$	67,959.30		$	72,891.30
	Operating revenues (loss):
	Commodity and Risk Management Services	$	221.7	$	242.5		$	248.5
	Foreign Exchange	66.9		62.6			59.3
	Securities	61.1		39.9			30.5
	Clearing and Execution Services	100.8		93.8			66.1
	Other	20.7		15.6			14.3
	Corporate unallocated	7.2		(0.2		)	0.4
	Total	$	478.4	$	454.2		$	419.1
	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	$	131.1	$	139.5		$	147.5
	Foreign Exchange	44		41.3			37.1
	Securities	30.5		19.8			16.5
	Clearing and Execution Services	15.3		14.3			14.3
	Other	13.2		10.3			10
	Total	$	234.1	$	225.2		$	225.4
	Segment income:
	(Net contribution less non-variable direct segment costs):
	Commodity and Risk Management Services	$	59.6	$	66.2		$	89.4
	Foreign Exchange	29.8		28.3			28
	Securities	13.9		4.5			1.9
Clearing and Execution Services	1.9		2.2			4.9
Other	9.1		5.4			5.6
Total	$	114.3	$	106.6		$	129.8
Reconciliation of segment income to income from continuing operations, before tax:
Segment income	$	114.3	$	106.6		$	129.8
Costs not allocated to operating segments	91.7		90.8			74.4
Income from continuing operations, before tax	$	22.6	$	15.8		$	55.4
(in millions)	As of September 30, 2013		As of September 30, 2012			As of September 30, 2011
			(As Restated)			(As Restated)
Total assets:
Commodity and Risk Management Services	$	1,105.10	$	1,439.70		$	1,534.80
Foreign Exchange	145		124.5			146.1
Securities	198.5		88.7			104.8
Clearing and Execution Services	1,246.40		1,090.90			734.4
Other	37.3		110.8			43.4
Corporate unallocated	115.7		98.4			68.5
Total	$	2,848.00	$	2,953.00		$	2,632.00
Information regarding revenues and operating revenues for the years ended September 30, 2013, 2012 and 2011, and information regarding long-lived assets (defined as property, equipment, leasehold improvements and software) as of September 30, 2013, 2012 and 2011 in geographic areas were as follows:
	Year Ended September 30,
(in millions)	2013		2012			2011
			(As Restated)			(As Restated)
Total revenues:
United States	$	29,062.00	$	53,398.00		$	48,165.30
Europe	65.6		69.9			35.1
South America	51.3		58.2			53.3
Asia	14,582.10		14,420.80			24,627.00
Other	7.3		12.4			10.6
Total	$	43,768.30	$	67,959.30		$	72,891.30
Operating revenues:
United States	$	333.9	$	293.8		$	298
Europe	65.6		69.9			35.1
South America	51.3		58.2			53.3
Asia	20.3		19.9			27.6
Other	7.3		12.4			5.1
Total	$	478.4	$	454.2		$	419.1
(in millions)	As of September 30, 2013		As of September 30, 2012			As of September 30, 2011
Long-lived assets, as defined:
United States	$	9.1	$	11.5		$	10.7
Europe	5.4		3.8			2
South America	2.4		2.8			1.6
Asia	0.5		0.7			0.6
Other	0.1		0.1			0.1
Total	$	17.5	$	18.9		$	15

Subsequent_Events

Subsequent Events	12 Months Ended
	Sep. 30, 2013
Subsequent Events [Abstract]	'
Subsequent Events [Text Block]	'
	Subsequent Events
	On November 15, 2013, the Company’s subsidiary INTL FCStone, Ltd entered into a credit agreement under which $25 million is available to INTL FCStone, Ltd. to provide short-term funding of margin to commodity exchanges as necessary, and for general corporate purposes of INTL FCStone, Ltd. This line of credit is subject to annual review, and the continued availability of this line of credit is subject to INTL FCStone, Ltd.’s financial condition and operating results continuing to be satisfactory as set forth in the agreement. The facility is guaranteed by the Company.
	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.

Condensed_Parent_Only_Financia1

Condensed Parent Only Financial Statements [Schedule]	12 Months Ended
	Sep. 30, 2013
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'
Condensed Financial Information of Parent Company Only Disclosure [Text Block]	'
	Schedule I
	INTL FCStone Inc.
	Condensed Balance Sheets
	Parent Company Only
	(in millions)	September 30,			September 30,
		2013			2012
	ASSETS
	Cash and cash equivalents	$	3.1		$	13.1
	Receivable from subsidiaries	22.9			20.1
	Notes receivable, net	27.3			10.2
	Income taxes receivable	17.5			14.3
	Financial instruments owned, at fair value	—			1.5
	Investment in subsidiaries(1)	237.3			220.1
	Deferred income taxes	7.1			0.9
	Property and equipment, net	3.6			4.3
	Goodwill and intangible assets, net	—			—
	Other assets	4.3			3.4
	Total assets	$	323.1		$	287.9
	LIABILITIES AND EQUITY
	Liabilities:
	Accounts payable and other accrued liabilities	$	11.1		$	4.2
	Payable to customers	18.7			0.7
	Payable to lenders under loans	55			48
	Senior unsecured notes	45.5			—
	Financial instruments sold, not yet purchased, at fair value	0.6			25.3
	Total liabilities	130.9			78.2
	Equity:
	INTL FCStone Inc. (Parent Company Only) stockholders’ equity:
	Preferred stock, $0.01 par value. Authorized 1,000,000 shares; no shares issued or outstanding	—			—
	Common stock, $0.01 par value. Authorized 30,000,000 shares; 19,638,330 issued and 19,209,157 outstanding at September 30, 2013 and 19,214,219 issued and 18,984,951 outstanding at September 30, 2012	0.2			0.2
	Common stock in treasury, at cost - 429,173 shares at September 30, 2013 and 229,064 shares at September 30, 2012	(7.8		)	(4.1		)
	Additional paid-in capital	224			213.2
	Retained earnings(1)	(24.2		)	0.4
	Total INTL FCStone Inc. (Parent Company Only) stockholders’ equity	192.2			209.7
	Total liabilities and equity	$	323.1		$	287.9
	(1) Within the Condensed Balance Sheets and Condensed Statements of Operations of INTL FCStone Inc. - Parent Company Only, the Company has accounted for its investment in wholly owned subsidiaries using the cost method of accounting. Under this method, the Company’s share of the earnings or losses of such subsidiaries are not included in the Condensed Balance Sheet or Condensed Statements of Operations. If the accounting for its investment in wholly owned subsidiaries were presented under the equity method of accounting, investment in subsidiaries and retained earnings would each increase by $149.6 million as of September 30, 2013, respectively, and $105.7 million, as restated, as of September 30, 2012, respectively.
	Schedule I
	INTL FCStone Inc.
	Condensed Statements of Operations
	Parent Company Only
		Year Ended September 30,
	(in millions)	2013			2012			2011
	Revenues:
	Trading gains, net	$	7.2		$	7.1		$	3.1
	Consulting and management fees	1.6			0.2			—
	Interest income	3.6			2.1			4.3
	Other income(2)	2			0.1			0.4
	Total revenues	14.4			9.5			7.8
	Interest expense	7.1			5.6			9.7
	Net revenues	7.3			3.9			(1.9		)
	Non-interest expenses:
	Compensation and benefits	30.5			12.4			8.6
	Clearing and related expenses	0.5			0.3			0.1
	Introducing broker commissions	0.5			—			0.2
	Communication and data services	0.9			0.6			0.5
	Occupancy and equipment rental	1.4			1			1.2
	Professional fees	2.3			3.1			3.8
	Travel and business development	1.2			1.4			0.5
	Depreciation and amortization	1.5			1.2			0.6
	Bad debts and impairments	—			2.2			—
	Other	6.3			5.4			(1.0		)
	Total non-interest expenses	45.1			27.6			14.5
	Loss from continuing operations, before tax	(37.8		)	(23.7		)	(16.4		)
Income tax benefit	13.2			9.2			6.4
Net loss	$	(24.6	)	$	(14.5	)	$	(10.0	)
(2) Within the Condensed Balance Sheets and Condensed Statements of Operations of INTL FCStone Inc. - Parent Company Only, the Company has accounted for its investment in wholly owned subsidiaries using the cost method of accounting. Under this method, the Company’s share of the earnings or losses of such subsidiaries are not included in the Condensed Balance Sheet or Condensed Statements of Operations. If the accounting for its investment in wholly owned subsidiaries were presented under the equity method of accounting, revenues would include income from investment in subsidiaries of $43.9 million, $27.3 million, as restated, and $44.8 million, as restated, for the years ended September 30, 2013, 2012 and 2011, respectively.
Certain amounts previously reported have been reclassified to conform to the current period presentation.
Schedule I
INTL FCStone Inc.
Condensed Statements of Cash Flows
Parent Company Only
	Year Ended September 30,
(in millions)	2013			2012			2011
Cash flows from operating activities:
Net loss	$	(24.6	)	$	(14.5	)	$	(10.0	)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation and amortization	1.5			1.2			0.6
Provision for impairments	—			2.2			—
Deferred income taxes	(6.1		)	(0.1		)	1.1
Amortization of debt issuance costs and debt discount	0.5			0.5			0.2
Convertible debt interest settled in common stock upon conversion	—			—			0.2
Amortization of share-based compensation expense	9.3			5.9			2.3
Gain on acquisition of INTL Provident	—			—			(0.4		)
Changes in operating assets and liabilities:
Receivable from subsidiaries	(2.8		)	21.7			35.7
Notes receivable, net	(17.1		)	(10.2		)	—
Income taxes receivable	(3.2		)	7.1			(13.6		)
Financial instruments owned, at fair value	1.5			1.7			(0.4		)
Other assets	1.7			(0.3		)	(0.8		)
Accounts payable and other accrued liabilities	1.4			(2.2		)	1.7
Payable to customers	18			0.7			—
Financial instruments sold, not yet purchased, at fair value	(24.7		)	(33.4		)	(0.5		)
Net cash (used in) provided by operating activities	(44.6		)	(19.7		)	16.1
Cash flows from investing activities:
Capital contribution in affiliates	(11.5		)	(12.5		)	(1.0		)
Purchase of property and equipment	(0.8		)	(2.7		)	(1.7		)
Net cash used in investing activities	(12.3		)	(15.2		)	(2.7		)
Cash flows from financing activities:
Payable to lenders under loans	7			48			(11.9		)
Proceeds from issuance of senior unsecured notes	45.5			—			—
Share repurchase	(4.0		)	(4.0		)	—
Debt issuance costs	(3.2		)	(0.1		)	(1.2		)
Exercise of stock options	1.5			1.9			1.3
Income tax benefit on stock options and awards	0.1			0.2			—
Net cash provided by (used in) financing activities	46.9			46			(11.8		)
Net (decrease) increase in cash and cash equivalents	(10.0		)	11.1			1.6
Cash and cash equivalents at beginning of period	13.1			2			0.4
Cash and cash equivalents at end of period	$	3.1		$	13.1		$	2
Supplemental disclosure of cash flow information:
Cash paid for interest	$	3		$	2.1		$	3
Income taxes (received) paid, net of cash refunds	$	(1.6	)	$	0.1		$	10.8
Supplemental disclosure of non-cash investing and financing activities:
Conversion of subordinated notes to common stock, net	$	—		$	—		$	16.7

Description_of_Business_and_Si1

Description of Business and Significant Accounting Policies Accounting Policies (Policies)	12 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Basis of Accounting, Policy [Policy Text Block]	'
	Basis of Presentation
	The accompanying 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.
	Unless otherwise stated herein, all references to fiscal 2013, fiscal 2012, and fiscal 2011 refer to the Company’s fiscal years ended September 30.
Consolidation, Policy [Policy Text Block]	'
	The accompanying 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]	'
	Unless otherwise stated herein, all references to fiscal 2013, fiscal 2012, and fiscal 2011 refer to the Company’s fiscal years ended September 30.
Reclassifications [Text Block]	'
	Reclassifications
	Certain amounts previously reported 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 net income or consolidated assets and liabilities.
Use of Estimates, Policy [Policy Text Block]	'
	Use of Estimates
	The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“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. These estimates are based on management’s best knowledge of current events and actions the Company may undertake in the future. The Company reviews all significant estimates affecting the financial statements on a recurring basis and records the effect of any necessary adjustments prior to their issuance. Although these and other estimates and assumptions are based on the best available information, actual results could be materially different from these estimates.
Foreign Currency Transactions and Translations Policy [Policy Text Block]	'
	Foreign Currency Translation
	Assets and liabilities recorded in foreign currencies are translated at the exchange rates prevailing on the balance sheet date. Revenue and expenses are translated at average rates of exchange prevailing during the period. Gains or losses on translation of the financial statements of a non-United States (“U.S.”) operation, when the functional currency is other than the U.S. dollar, are recorded in other comprehensive income (“OCI”), net of tax, a component of stockholders’ equity. Foreign currency remeasurement gains or losses on transactions in nonfunctional currencies are included in ‘trading gains, net’ in the consolidated income statements.
Cash and Cash Equivalents, Unrestricted Cash and Cash Equivalents, Policy [Policy Text Block]	'
	Cash and Cash Equivalents
	The Company considers cash held at banks and all highly liquid investments, including certificates of deposit, which may be withdrawn at any time at the discretion of the Company without penalty, to be cash and cash equivalents. Cash and cash equivalents consist of cash, foreign currency, money market funds and certificates of deposit not deposited with or pledged to exchange-clearing organizations, broker-dealers, clearing organizations or counterparties. The money market funds are valued at period-end at the net asset value provided by the fund’s administrator, which approximates fair value. Certificates of deposit are stated at cost plus accrued interest, which approximates fair value. The Company has an investment policy, which limits the maximum amount placed in any one fund and with any one institution in order to reduce credit risk. The Company does not believe that it is exposed to significant risk on cash and cash equivalents.
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]	'
	Cash, Securities and Other Assets Segregated under Federal and other Regulations
	Pursuant to requirements of the Commodity Exchange Act in the U.S. and similarly in the United Kingdom (“UK”), pursuant to the Markets in Financial Instruments Implementing Directive 2006/73/EC underpinning the Client Asset or ‘CASS’ rules in the Financial Services Authority (“FSA”) handbook, funds deposited by customers relating to futures and options-on-futures contracts in regulated commodities must be carried in separate accounts which are designated as segregated customer accounts. The deposits in segregated customer accounts are not commingled with the funds of the Company. Under the FSA’s rules, certain categories of clients may choose to opt-out of segregation. As of September 30, 2013 and 2012, cash, securities and other assets segregated under federal and other regulations consisted of cash held at banks and money market funds of approximately $416.8 million and $284.7 million, respectively, U.S. government securities and federal agency obligations of approximately $19.5 million and $50.5 million, respectively, and commodities warehouse receipts of approximately $13.1 million and $22.3 million, respectively (see fair value measurements discussion in Note 4).
Repurchase and Resale Agreements Policy [Policy Text Block]	'
	Securities purchased under agreements to resell
	The Company has an overnight sweep reverse repurchase agreement program to allow the Company to enter into secured overnight investments (reverse repurchase agreements or reverse repos), which generally provides a higher investment yield than a regular operating account. The reverse repurchase agreements are recorded at amounts at which the securities were initially acquired. It is the policy of the Company to take possession of the securities purchased under agreements to resell. The Company receives U.S. Treasury securities as collateral for the overnight agreements. The securities received are recorded at no more than the lesser of the current fair value of the securities or the net amount to be realized by the Company upon resale of the securities. The maturity of the reverse repurchase agreements is typically one day, at which point the securities are sold and the proceeds are returned to the Company, plus any accrued interest. There were no agreements to resell securities as of September 30, 2013 and 2012.
	Commodity and Other Repurchase Agreements
	In the normal course of operations the Company accepts notes receivable under sale/repurchase agreements with customers whereby the customers sell certain commodity inventory or other investments and agree to repurchase the commodity inventory or investment at a future date at either a fixed or floating rate. These transactions are short-term in nature, and in accordance with the guidance contained in the Transfers and Servicing Topic of the ASC, are treated as secured borrowings rather than commodity inventory and purchases and sales in the Company’s consolidated financial statements.
	Additionally, the Company participates in transactions involving commodities or other investments sold under repurchase agreements (“repos”). In accordance with the guidance contained in the Transfers and Servicing Topic of the ASC, these transactions are treated as secured borrowings that are recorded as a liability in the consolidated balance sheets. Commodities or investments sold under repurchase agreements are reflected at the amount of cash received in connection with the transactions. The Company may be required to provide additional collateral based on the fair value of the underlying asset.
Due to and from Broker-Dealers and Clearing Organizations Disclosure [Text Block]	'
	Deposits and Receivables from Exchange-Clearing Organizations, Broker-dealers, Clearing Organizations and Counterparties, and Payables to Broker-dealers, Clearing Organizations and Counterparties
	As required by the regulations of the U.S. Commodity Futures Trading Commission (“CFTC”) and the Markets in Financial Instruments Implementing Directive 2006/73/EC underpinning the CASS rules in the FSA handbook, customer funds received to margin, guarantee, and/or secure commodity futures transactions are segregated and accounted for separately from the general assets of the Company. Under the FSA’s rules, certain categories of clients may choose to opt-out of segregation. Deposits with exchange-clearing organizations, broker-dealers and counterparties pertain primarily to deposits made to satisfy margin requirements on customer and proprietary open futures and options-on-futures positions and to satisfy the requirements set by clearing exchanges for clearing membership. The Company also pledges margin deposit with various counterparties for OTC derivative contracts, and these deposits are also included in deposits and receivables from broker-dealers and counterparties. Deposits with and receivables from exchange-clearing organizations and broker-dealers and counterparties are reported gross, except where a right of offset exists. As of September 30, 2013 and 2012, the Company had cash and cash equivalents on deposit with or pledged to exchange-clearing organizations, broker-dealers and counterparties of $1.0 billion and $0.4 billion, respectively.
	These balances also include securities pledged by the Company on behalf of customers and customer-owned securities that are pledged. It is the Company’s practice to include customer owned securities on its consolidated balance sheets, as the rights to those securities have been transferred to the Company under the terms of the futures trading agreement. Securities pledged include U.S. Treasury bills and instruments backed by U.S. government sponsored entities and government-sponsored enterprise backed mortgage-backed securities (“mortgage-backed securities”). The securities that are not customer-owned are adjusted to fair value with associated changes in unrealized gains or losses recorded in OCI, net of tax, until realized, a component of stockholders’ equity. For customer owned securities, the change in fair value is offset against the payable to customers with no impact recognized on the consolidated income statements.
	The securities, primarily U.S. Government obligations and mortgage-backed securities, held by FCStone LLC (“FCStone”), a subsidiary of INTL, as collateral or as margin have been deposited with exchange-clearing organizations, broker-dealers or other counterparties. The fair value of these securities was approximately $0.6 billion and $1.3 billion as of September 30, 2013 and 2012, respectively.
	Management has considered guidance required by the Transfers and Servicing Topic of the ASC as it relates to securities pledged by customers to margin their accounts. Based on a review of the agreements with the customer, management believes a legal basis exists to support that the transferor surrenders control over those assets if all of the following three conditions are met: (a) the transferred assets have been isolated from the transferor—put presumptively beyond the reach of the transferor and its creditors, even in bankruptcy or other receivership, (b) each transferee has the right to pledge or exchange the assets (or beneficial interests) it received, and no condition both constrains the transferee (or holder) from taking advantage of its right to pledge or exchange and provides more than a trivial benefit to the transferor and (c) the transferor does not maintain effective control over the transferred assets through either (1) an agreement that both entitles and obligates the transferor to repurchase or redeem them before their maturity or (2) the ability to unilaterally cause the holder to return specific assets, other than through a cleanup call. Under this guidance, the Company reflects the customer collateral assets and corresponding liabilities in the Company’s consolidated balance sheets as of September 30, 2013 and 2012.
	In addition to margin, deposits with exchange-clearing organizations include guaranty deposits. The guaranty deposits are held by the clearing organization for use in potential default situations by one or more members of the clearing organization. The guaranty deposits may be applied to the Company’s obligations to the clearing organization, or to the clearing organization’s obligations to other clearing members or third parties.
	The Company maintains customer omnibus and proprietary accounts with other counterparties, and the equity balances in those accounts along with any margin cash or securities deposited with the carrying broker are included in deposits and receivables from broker-dealers and counterparties.
	Receivables from and payables to exchange-clearing organizations are also comprised of amounts due from or due to exchange-clearing organizations for daily variation settlements on open futures and options-on-futures positions. The variation settlements due from or due to exchange-clearing organizations are paid in cash on the following business day.
	Deposits and receivables with exchange-clearing organizations also includes the unrealized gains and losses associated with the customers’ options-on-futures contracts. See discussion in the Financial Instruments and Derivatives section below for additional information on the treatment of derivative contracts. For customer owned derivative contracts, the fair value is offset against the payable to customers with no impact recognized on the consolidated income statements.
Trade and Other Accounts Receivable, Policy [Policy Text Block]	'
	Receivable from and Payable to Customers
	Receivable from customers, net of the allowance for doubtful accounts, include the total of net deficits in individual exchange-traded and OTC trading accounts carried by the Company. Customer deficits arise from realized and unrealized trading losses on futures, options-on-futures, swaps and forwards and amounts due on cash and margin transactions. Customer deficit accounts are reported gross of customer accounts that contain net credit or positive balances, except where a right of offset exists. Net deficits in individual exchange-traded and OTC trading accounts include both secured and unsecured deficit balances due from customers as of the balance sheet date. Secured deficit amounts are backed by U.S. Treasury bills and notes and commodity warehouse receipts. These U.S Treasury bills and notes and commodity warehouse receipts are not netted against the secured deficit amounts, as the conditions for right of setoff have not been met.
	Payable to customers represent the total of customer accounts with credit or positive balances. Customer accounts are used primarily in connection with commodity transactions and include gains and losses on open commodity trades as well as securities and other deposits made as required by the Company or the exchange-clearing organizations or counterparties. Customer accounts with credit or positive balances are reported gross of customer deficit accounts, except where a right of offset exists.
	For regulatory purposes, certain customers, which would include persons who are affiliated with the Company or are principals, such as an officer or director, and any person who is materially involved in the management of the Company, are identified as noncustomers. A noncustomer account may not be carried as a customer account due to an affiliation with the Company. In a liquidation event, amounts owed to noncustomers are paid in the same priority as amounts owed to general creditors of the Company. These accounts are also referred to as proprietary accounts. The amounts related to noncustomer accounts are included in ‘payable to customers’ on the consolidated balance sheets.
	The future collectability of the receivable from customers can be impacted by the Company’s collection efforts, the financial stability of its customers, and the general economic climate in which it operates. The Company evaluates accounts that it believes may become uncollectible on a specific identification basis, through reviewing daily margin deficit reports, the historical daily aging of the receivables, and by monitoring the financial strength of its customers. The Company may unilaterally close customer trading positions in certain circumstances. In addition, to evaluate customer margining and collateral requirements, customer positions are stress tested regularly and monitored for excessive concentration levels relative to the overall market size.
	The Company generally charges off an outstanding receivable balance when all economically sensible means of recovery have been exhausted. That determination considers information such as the occurrence of significant changes in the customer’s financial position such that the customer can no longer pay the obligation, or that the proceeds from collateral will not be sufficient to pay the balance.
Finance, Loans and Leases Receivable, Policy [Policy Text Block]	'
	Notes Receivable
	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 Company may sell the insured portion of the notes through non-recourse participation agreements with other third parties. See discussion of notes receivable related to commodity repurchase agreements below.
	Accrual of commodity financing income on any note is discontinued when, in the opinion of management, there is reasonable doubt as to the timely collectability of interest or principal. Nonaccrual notes are returned to an accrual status when, in the opinion of management, the financial position of the borrower indicates there is no longer any reasonable doubt as to the timely payment of principal and interest. The Company records a charge against earnings for notes receivable losses when management believes that collectability of the principal is unlikely.
Inventory, Policy [Policy 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 costing method. Cost includes finished commodity or raw material and processing costs related to the purchase and processing of inventories.
Property, Plant and Equipment, Policy [Policy Text Block]	'
	Property and Equipment
	Property and equipment is stated at cost, net of accumulated depreciation and amortization and depreciated using the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized on a straight-line basis over the estimated useful life of the improvement or the term of the lease, whichever is shorter. Certain costs of software developed or obtained for internal use are capitalized and amortized over the estimated useful life of the software. Expenditures for maintenance, repairs, and minor replacements are charged against earnings, as incurred. Expenditures that increase the value or productive capacity of assets are capitalized. When property and equipment are retired, sold, or otherwise disposed of, the asset’s carrying amount and related accumulated depreciation are removed from the accounts and any gain or loss is included in earnings.
Goodwill and Intangible Assets, Policy [Policy Text Block]	'
	Goodwill and Identifiable Intangible Assets
	Goodwill is the cost of acquired companies in excess of the fair value of identifiable net assets at acquisition date. In accordance with the Intangibles – Goodwill and Other Topic of the ASC, goodwill is tested for impairment on an annual basis at the fiscal year-end, and between annual tests if indicators of potential impairment exist, using a fair-value-based approach. No impairment of goodwill has been identified during any of the periods presented.
	Identifiable intangible assets subject to amortization are amortized using the straight-line method over their estimated period of benefit, ranging from two to twenty years. Identifiable intangible assets are tested for impairment whenever events or changes in circumstances suggest that an asset’s or asset group’s carrying value may not be fully recoverable in accordance with the Intangibles – Goodwill and Other Topic of the ASC. Residual value is presumed to be zero. Identifiable intangible assets not subject to amortization are reviewed at each reporting period to reevaluate if the intangible asset’s useful life remains indefinite. Additionally, intangible assets not subject to amortization are tested annually for impairment at the fiscal year-end, and between annual tests if indicators of potential impairment exist, using a fair-value-based approach. See Note 10 for discussion of impairments of intangible assets that have been identified during the fiscal years ended September 30, 2013 and 2012.
Investment, Policy [Policy Text Block]	'
	Financial Instruments and Derivatives
	Financial instruments owned and sold, not yet purchased, at fair value consist of financial instruments carried at fair value or amounts that approximate fair value, with related unrealized changes in gains or losses recognized in earnings, except for securities classified as available-for-sale. The fair value of a financial instrument is the amount at which the instrument could be exchanged in a current transaction between willing parties, other than in a forced or liquidation sale.
	The Company accounts for its securities pledged on behalf of customers and proprietary securities in accordance with the Investments - Debt and Equity Securities Topic in the ASC. In accordance with this guidance, the Company determines the appropriate classification of its investments as trading, available-for-sale, or held-to-maturity at the time of purchase and reevaluates the designation as of each reporting period.
	The Company has classified certain U.S. government obligations, corporate debt securities and exchange firm common stock not pledged for clearing purposes as available-for-sale, which are carried at fair value based on observable or quoted market prices and associated unrealized gains or losses are recorded as a component of OCI, net of tax, until realized, unless an unrealized loss is determined to be other than temporary, in which case such loss is charged to earnings. The Company classifies those securities as available-for-sale because it would consider selling them prior to maturity to meet liquidity needs or as part of the Company’s risk management program.
	The Company computes the cost of its securities on a specific identification basis. Such cost includes the direct costs to acquire securities, adjusted for the amortization of any discount or premium. The amortized cost of securities is computed under the effective-interest method and is included in interest income. Realized gains and losses, declines in value judged to be other than temporary and interest on available-for-sale securities are included in earnings.
	Investment in managed funds, at fair value represents investments in funds managed by the Company’s fund managers. The investments are valued at period-end at the net asset value provided by the fund’s administrator.
	Commodities warehouse receipts are valued at the cash price, or the nearby futures prices in the absence of a cash price, for the commodity based on published market quotes. For commodities warehouse receipts, the change in fair value is offset against the payable to customers with no impact on the consolidated income statements.
	The Company utilizes derivative instruments to manage exposures to foreign currency, commodity price and interest rate risks for the Company and its customers. The Company’s objectives for holding derivatives include reducing, eliminating, and efficiently managing the economic impact of these exposures as effectively as possible. Derivative instruments are recognized as either assets or liabilities and are measured at fair value. The accounting for changes in the fair value of a derivative depends on the intended use of the derivative and the resulting designation. For a derivative instrument designated as a cash flow hedge, the effective portion of the derivative’s gain or loss is initially recorded in OCI, net of tax, and is subsequently recognized in earnings when the hedged exposure affects earnings. The ineffective portion of the gain or loss is recognized in earnings. Gains and losses from changes in fair values of derivatives that are not designated as cash flow hedges for accounting purposes are recognized in earnings.
	The Company’s derivative contracts consist of exchange-traded and OTC derivatives. Fair values of exchange-traded derivatives are generally determined from quoted market prices. OTC derivatives are valued using valuation models. The valuation models used to derive the fair values of OTC derivatives require inputs including contractual terms, market prices, yield curves and measurements of volatility. The Company uses similar models to value similar instruments. Where possible, the Company verifies the values produced by pricing models by comparing them to market transactions. Inputs may involve judgment where market prices are not readily available. The Company does not elect hedge accounting under the Derivatives and Hedging Topic of the ASC in accounting for derivatives used as economic hedges on its commodities.
	The Company provides clearing and execution of exchange-traded futures and options-on-futures for middle-market intermediaries, end-users, producers of commodities and the institutional and professional trader market segments. The Company has a subsidiary that is a registered futures commission merchant (“FCM”), clearing on various exchanges. The primary sources of revenues for the Company’s FCM are commissions and clearing fees derived from executing and clearing orders for commodity futures contracts and options-on-futures on behalf of its customers.
	The Company also brokers foreign exchange forwards, options and cash, or spot, transactions between customers and external counterparties. A portion of the contracts are arranged on an offsetting basis, limiting the Company’s risk to performance of the two offsetting parties. The offsetting nature of the contracts eliminates the effects of market fluctuations on the Company’s operating results. Due to the Company’s role as a principal participating in both sides of these contracts, the amounts are presented gross on the consolidated balance sheets at their respective fair values, net of offsetting assets and liabilities.
	In addition, the Company engages in speculative trading and holds proprietary positions in futures, options, swaps and forward derivatives, including corn, wheat, soybeans, sugar and foreign currency contracts. Since some of the derivatives held or sold by the Company are for speculative trading purposes, these derivative instruments are not designated as hedging instruments and accordingly, the changes in fair value during the period are recorded in the consolidated income statements as a component of ‘trading gains, net’ (see Note 5).
	The Company also holds proprietary positions in its foreign exchange line of business. On a limited basis, the Company’s foreign exchange trade desk will accept a customer transaction and will offset that transaction with a similar but not identical position with a counterparty. These unmatched transactions are intended to be short-term in nature and are often conducted to facilitate the most effective transaction for the Company’s customer. These spot and forward contracts are accounted for as free-standing derivatives and reported in the consolidated balance sheets at their fair values. The Company does not seek hedge accounting treatment for these derivatives, and accordingly, the changes in fair value during the period are recorded in the consolidated income statements in ‘trading gains, net’ (see Note 5). In applying the guidance in the Balance Sheet-Offsetting Topic of the ASC, the Company’s accounting policy is such that open contracts with the same customer are netted at the account level, in accordance with netting arrangements in place with each party, as applicable and rights to reclaim cash collateral or obligations to return cash collateral are netted against fair value amounts recognized for derivative instruments with the same customer in accordance with the master netting arrangements in place with each customer.
	The Company may lease commodities to or from customers or counterparties, or advance commodities to customers on an unpriced basis, receiving payment when they become priced. These are valued at fair value utilizing the fair value option based on guidance in the Financial Instruments Topic of the ASC. As permitted by the fair value option election, the entire instrument is recorded at fair value in the consolidated balance sheets as a component of ‘financial instruments owned and sold, not yet purchased’. Due to the short term nature of the instruments, the balance of the agreements is not materially different than the recorded fair value. The corresponding change in fair value of the instrument is recognized in the consolidated income statements as a component of ‘trading gains, net’ for the fiscal years ended 2013, 2012 and 2011. The Company does elect to value all of their commodities lease agreements at fair value using the fair value option. See fair value measurements in Note 4.
Exchange Memberships, Policy [Policy Text Block]	'
	Exchange Memberships and Stock
	The Company is required to hold certain exchange membership seats and exchange firm common stock and pledge them for clearing purposes, in order to provide the Company the right to process trades directly with the various exchanges. Exchange memberships include seats on the Chicago Board of Trade (“CBOT”), the Minneapolis Grain Exchange, the New York Mercantile Exchange (“NYMEX”), the Commodity Exchange, Inc. (“COMEX”) Division of the New York Mercantile Exchange, Mercado de Valores de Buenos Aires S.A. (“MERVAL”), the Chicago Mercantile Exchange (“CME”) Growth and Emerging Markets, InterContinental Exchange, Inc. (“ICE”) Futures US, ICE Europe Ltd and London Metal Exchange (“LME”). Exchange firm common stock include shares of CME Group, Inc., ICE and LME. In December 2012, the CME completed its acquisition of the Board of Trade of Kansas City, Missouri, Inc. (“KCBT”). The Company received proceeds of $1.5 million and recognized a gain of $0.9 million before taxes, in connection with its class A shares of the KCBT held as of September 30, 2012, during the fiscal year ended September 30, 2013.
	Exchange memberships and firm common stocks pledged for clearing purposes are recorded at cost, in accordance with U.S. GAAP and CFTC regulations and are included in ‘other assets’ on the consolidated balance sheets. Equity investments in exchange firm common stock not pledged for clearing purposes are classified as available-for-sale and recorded at fair value, with unrealized gains and losses recorded as a component of OCI, net of tax, until realized. Equity investments in exchange firm common stock not pledged for clearing purposes are included in ‘financial instruments owned’ on the consolidated balance sheets.
	The cost basis for exchange memberships and firm common stock pledged for clearing purposes was $10.4 million and $10.5 million as of September 30, 2013 and 2012, respectively. The fair value of exchange memberships and firm common stock pledged for clearing purposes was $8.5 million and $8.9 million as of September 30, 2013 and 2012, respectively. The fair value of exchange firm common stock is determined by quoted market prices, and the fair value of exchange memberships is determined by recent sale transactions. The Company monitors the fair value of exchange membership seats and firm common stock on a quarterly basis, and does not consider any current unrealized losses on individual exchange memberships to be anything other than a temporary impairment.
Business Combinations Policy [Policy Text Block]	'
	Business Combinations
	Acquisitions during fiscal 2013 and fiscal 2012 are accounted for as business combinations in accordance with the provisions of the Business Combinations Topic of the ASC. Under this accounting guidance most of the assets and liabilities acquired and assumed are measured at fair value as of the acquisition date. Certain contingent liabilities acquired require remeasurement at fair value in each subsequent reporting period. Noncontrolling interests are initially measured at fair value and classified as a separate component of equity. Acquisition related costs, such as fees for attorneys, accountants, and investment bankers, are expensed as incurred and are not capitalized as part of the purchase price. For all acquisitions, regardless of the consummation date, deferred tax assets, valuation allowances, and uncertain tax position adjustments occurring after the measurement period are recorded as a component of income, rather than adjusted through goodwill.
	Determining the fair value of certain assets and liabilities acquired is subjective in nature and often involves the use of significant estimates and assumptions. Estimating the fair value of the assets and liabilities acquired requires significant judgment.
	Contingent Consideration
	The Company estimates and records the acquisition date estimated fair value of contingent consideration as part of purchase price consideration for acquisitions. Additionally, each reporting period, the Company estimates changes in the fair value of contingent consideration, and any change in fair value is recognized in the consolidated income statement. An increase in the earn-out expected to be paid will result in a charge to operations in the period that the anticipated fair value of contingent consideration increases, while a decrease in the earn-out expected to be paid will result in a credit to operations in the period that the anticipated fair value of contingent consideration decreases. The estimate of the fair value of contingent consideration requires subjective assumptions to be made of future operating results, discount rates, and probabilities assigned to various potential operating result scenarios. Future revisions to these assumptions could materially change the estimate of the fair value of contingent consideration and, therefore, materially affect the Company’s future financial results.
Stockholders' Equity, Policy [Policy Text Block]	'
	Additional Paid-In Capital
	The Company’s additional paid-in capital (“APIC”) consists of stockholder contributions that are in excess of par value of common stock. Included in APIC are amounts related to the exercise of stock options, share-based compensation and shares held in escrow.
	In September 2010, the Company acquired certain assets of Provident Group (“Provident”). The purchase price for the assets and services of the sellers was $5.0 million. Subsequent to closing, the individual sellers placed the entire purchase price into an escrow account and the funds were used to purchase outstanding shares of the Company on the open market. There were 214,325 shares purchased and placed into escrow as a result of this agreement. The entire purchase price was recorded as a reduction in additional paid in capital as shares held in escrow for business combinations. The shares held in escrow for business combinations will be released to the individual sellers, over a five year period from the date of closing based on net profits, in accordance with the provisions of the acquisition agreement. However, if the terms of the agreement are not met, the remaining shares will be forfeited and the remaining shares and balance in the shares held in escrow for business combinations will be recorded as treasury stock. In accordance with the acquisition agreement, 6,799 and 3,255 shares were earned and subsequently released to the sellers during the years ended September 30, 2013 and 2012, respectively.
Revenue Recognition, Policy [Policy Text Block]	'
	Revenue Recognition
	Sales of physical commodities revenue are recognized when persuasive evidence of an arrangement exists, delivery has occurred, the fee is fixed or determinable, and collectability is reasonably assured. The Company reports its physical commodities revenues on a gross basis, with the corresponding cost of sales shown separately, in accordance with the guidelines provided in the Revenue Recognition Topic of the ASC.
	Trading gains, net include brokerage fees and margins generated from OTC derivative trades executed with customers and other counterparties and are recognized when trades are executed. Trading gains, net also include activities where the Company acts as principal in the purchase and sale of individual securities, currencies, commodities or derivative instruments with customers. These transactions may be offset simultaneously with another customer or counterparty, offset with similar but not identical positions on an exchange, made from inventory, or may be aggregated with other purchases to provide liquidity intraday, for a number of days, or in some cases, particularly the base metals business, even longer periods (during which fair value may fluctuate). In addition, trading gains, net includes activities from the Company’s operations of a proprietary foreign exchange desk which arbitrages the futures and cash markets (see additional discussion in the Financial Instruments and Derivatives policy note for revenue recognition on proprietary trading activities). Net dealer inventory and investment gains are recognized on a trade-date basis and include realized gains or losses and changes in unrealized gains or losses on investments at fair value. Dividend income and dividend expense, on short equity positions, are recognized net, in ‘trading gain, net’ on the ex-dividend date.
	Commissions on futures contracts are recognized on a half-turn basis in two equal parts. The first half is recognized when the contract is opened and the second half is recognized when the transaction is closed. Commissions on options-on-futures contracts are generally recognized on a half-turn basis, except that full commissions are recognized on options expected to expire without being exercised or offset. Commissions and fees are charged at various rates based on the type of account, the products traded, and the method of trade. Clearing and transaction fees are charged to customers on a per exchange contract basis based on the trade date. Such fees are for clearing customers’ exchange trades and include fees charged to the Company by the various futures exchanges. See discussion of transaction-based clearing expenses below.
	Consulting and management fees include risk management consulting fees which are billed and recognized as revenue on a monthly basis when risk management services are provided. Such agreements are generally for one year periods, but are cancelable by either party upon providing thirty days written notice to the other party and the amounts are not variable based on customer trading activities. Asset management fees are recognized as they are earned based on fees due at each period-end date. These include performance fees based on the amount that is due under the formula for exceeding performance targets as of the period-end date. Fee income for structuring and arrangement of debt transactions and management and investment advisory income is recorded when the services related to the underlying transactions are provided and success fees are recorded when complete, as determined under the terms of the assignment or engagement.
	Interest income, generated primarily from investments and customer inventory financing, is recognized on an accrual basis. Interest from investments is generated from securities purchased using customer funds deposited with the Company to satisfy margin requirements, net of interest returned to customers, and from securities acquired through internally-generated company funds. Interest also includes unrealized gains and losses on securities owned and those deposited with other parties.
	Revenue generally is recognized net of any taxes collected from customers and subsequently remitted to governmental authorities.
Cost of Sales, Policy [Policy Text Block]	'
	Cost of Revenue
	Cost of sales of physical commodities include finished commodity or raw material and processing costs along with operating costs relating to the receipt, storage and delivery of the physical commodities.
Compensation Related Costs, Policy [Policy Text Block]	'
	Compensation and Benefits
	Compensation and benefits consists primarily of salaries, incentive compensation, commissions, related payroll taxes and employee benefits. The Company classifies employees as either traders / risk management consultants, operational or administrative personnel, which includes the executive officers. The most significant component of the Company’s compensation expense is the employment of the traders / risk management consultants, who are paid commissions based on the revenues that their customer portfolios generate. The Company accrues commission expense on a trade date basis.
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	'
	Share-Based Compensation
	The Company accounts for share-based compensation in accordance with the guidance of the Compensation-Stock Compensation Topic of the ASC. The cost of employee services received in exchange for a share-based award is generally measured based on the grant-date fair value of the award. Share-based employee awards that require future service are amortized over the relevant service period. Expected forfeitures are included in determining share-based employee compensation expense. In the first quarter of 2006, the Company adopted the guidance under the Compensation-Stock Compensation Topic of the ASC using the modified prospective method. For option awards granted subsequent to the adoption, compensation cost is recognized on a straight-line basis over the vesting period for the entire award. The expense of unvested option awards granted prior to the adoption are recognized on a straight-line basis, over the balance of the vesting period.
Floor Brokerage, Policy [Policy Text Block]	'
	Transaction-Based Clearing Expenses
	Clearing fees and related expenses include primarily variable expenses for clearing and settlement services, including fees the Company pays to executing brokers, exchanges, clearing organizations and banks. These fees are based on transaction volume, and recorded as expense on the trade date. Clearing fees are passed on to customers and are presented gross in the consolidated statements of income under the Revenue Recognition Topic of the ASC, as the Company acts as a principal for these transactions.
Commissions Expense, Policy [Policy Text Block]	'
	Introducing Broker Commissions
	Introducing broker commissions include commissions paid to non-employee third parties that have introduced customers to the Company. Introducing brokers are individuals or organizations that maintain relationships with customers and accept futures and options orders from those customers. The Company directly provides all account, transaction and margining services to introducing brokers, including accepting money, securities and property from the customers. The commissions are determined and settled monthly.
Income Tax, Policy [Policy Text Block]	'
	Income Taxes
	Income tax expense includes U.S. federal, state and local and foreign income taxes. Certain items of income and expense are not reported in tax returns and financial statements in the same year. The tax effect of such temporary differences is reported as deferred income taxes. Tax provisions are computed in accordance with the Income Taxes Topic of the ASC.
Comprehensive Income, Policy [Policy Text Block]	'
	Comprehensive Income
	Comprehensive income consists of net income and other gains and losses affecting stockholders’ equity that, under U.S. GAAP, are excluded from net income. Other comprehensive income (loss) includes net actuarial losses from defined benefit pension plans, unrealized gains and losses on available-for-sale securities, gains and losses on foreign currency translations, and changes in the fair value of interest rate swap agreements, to the extent they are, or previously were, effective as cash flow hedges.
Consolidation, Variable Interest Entity, Policy [Policy Text Block]	'
	Noncontrolling Interest and Variable Interest Entities
	In accordance with the Consolidation Topic of the Accounting Standards Codification (“ASC”) the Company consolidates any variable interest entities for which it is the primary beneficiary, as defined. The Company applies the equity method of accounting when the Company does not have a controlling interest in an entity, but exerts significant influence over the entity.
	The Company had a majority interest in and was the general partner of the Blackthorn Multi-Advisor Fund, LP (the “Blackthorn Fund”), whose assets, liabilities, income and expenses were included in the Company’s consolidated financial statements. During fiscal 2012, the Company redeemed its remaining investment in Blackthorn Fund effective December 31, 2011. As a result of the final redemption, the Company no longer retains any ownership interests in the Blackthorn Fund, has transferred its rights as general partner and deconsolidated its interest in the Blackthorn Fund as of December 31, 2011. The aggregate of the redemption and remaining noncontrolling interest less the carrying amount of the net assets of the Blackthorn Fund resulted in a nominal gain and was recorded as a component of ‘trading gains, net’ in the consolidated income statement for the year ended September 30, 2012, as a result of the deconsolidation.
Preferred Stock [Text Block]	'
	Preferred Stock
	The Company is authorized to issue one million shares of preferred stock, par value of $0.01 per share, in one or more classes or series to be established by the Company’s board of directors. As of September 30, 2013 and 2012, no preferred shares were outstanding and the Company’s board of directors had not yet established any class or series of shares.
New Accounting Pronouncements, Policy [Policy Text Block]	'
	Recent Accounting Pronouncements
	In June 2011, the Financial Accounting Standards Board (“FASB”) issued new guidance on the presentation of comprehensive income. This guidance eliminates the option to report comprehensive income and its components in the consolidated statement of stockholders’ equity. Under this guidance, an entity can elect to present items of net income and comprehensive income in one continuous statement or in two separate, but consecutive, statements. In addition, the guidance requires entities to show the effects of items reclassified from accumulated other comprehensive loss to net income on the face of the financial statements. This guidance is effective for fiscal years beginning after December 15, 2011 and interim and annual periods thereafter. Early adoption is permitted, but full retrospective application is required. This guidance was effective for the Company’s fiscal year 2013. The adoption of this guidance resulted in a change in the presentation of comprehensive income in the Company’s consolidated financial statements.
	In December 2011, the FASB issued new guidance on the disclosures about offsetting assets and liabilities. 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 expects to adopt this guidance starting with the first quarter of fiscal year 2014. The adoption of this guidance is expected to change some of the Company’s disclosures in the notes to its consolidated financial statements.
	In July 2012, the FASB issued final guidance on indefinite-lived intangible assets impairment testing. Under the guidance, entities testing indefinite-lived intangibles for impairment have the option of first performing a qualitative assessment to determine whether it is more likely than not that an indefinite-lived intangible asset is impaired. If a company determines that it is more likely than not that the fair value of such an asset exceeds its carrying amount, it would not need to calculate the fair value of the asset in that year. However, if a company concludes otherwise, it must calculate the fair value of the asset, compare that value with its carrying amount and record an impairment charge, if any. The guidance does not revise the requirement to test indefinite-lived intangible assets annually for impairment. In addition, the guidance does not amend the requirement to test indefinite-lived intangible assets for impairment between annual tests if events or circumstances warrant, however, it does revise the examples of events and circumstances that an entity should consider. The guidance is effective for annual and interim impairment tests performed for fiscal years beginning after September 15, 2012. Early adoption is permitted. The Company adopted this guidance and it did not have a material impact on the Company’s consolidated financial statements.
	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 expects to adopt this guidance starting with the first quarter of fiscal year 2014. The adoption of this guidance is not expected to have a material impact on the Company’s 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 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 consolidated financial statements.

Income_Taxes_Policies

Income Taxes (Policies)	12 Months Ended
	Sep. 30, 2013
Income Taxes [Abstract]	'
Income Tax, Policy [Policy Text Block]	'
	Income Taxes
	Income tax expense includes U.S. federal, state and local and foreign income taxes. Certain items of income and expense are not reported in tax returns and financial statements in the same year. The tax effect of such temporary differences is reported as deferred income taxes. Tax provisions are computed in accordance with the Income Taxes Topic of the ASC.

Restatement_of_Previously_Issu1

Restatement of Previously Issued Financial Statements (Tables)	12 Months Ended
	Sep. 30, 2013
Schedule of Error Corrections and Prior Period Adjustments [Table Text Block]	'
	The prior period consolidated balance sheet included in this filing has been restated to reflect the correction of these reconciliation errors noted above. The impact of the correction of the reconciliation errors to the Company’s previously reported consolidated balance sheet as of September 30, 2012 is summarized below.
	(in millions)	As of September 30, 2012
		(As Reported)		Cumulative Prior Period Adjustments		FY 2012 Adjustment		(As Restated)
	Deposits with and receivables from broker-dealers, clearing organizations and counterparties	$	127.4	(7.1	)	(3.5	)	$	116.8
	Income taxes receivable	$	11.9	2.3		1.3		$	15.5
	Goodwill and intangible assets, net	$	54.7	1.1		—		$	55.8
	Total assets	$	2,958.90	(3.7	)	(2.2	)	$	2,953.00
	Total liabilities	$	2,639.80	—		—		$	2,639.80
	Retained earnings	$	112	(3.7	)	(2.2	)	$	106.1
	Total stockholders’ equity	$	319.1	(3.7	)	(2.2	)	$	313.2
	Total liabilities and stockholders’ equity	$	2,958.90	(3.7	)	(2.2	)	$	2,953.00
	The impact of the correction of these errors to the Company's previously reported consolidated income statements for fiscal years ended September 30, 2012 and 2011 is summarized as follows:
		Consolidated Income Statement Information for the Year Ended September 30,
	(in millions, except share and per share amounts)	2012								2011
		(As Reported)		Adjustment		(As Restated)				(As Reported)		Adjustment		(As Restated)
	Sales of physical commodities	$	68,812.50	(1,297.8	)	$	67,514.70			$	75,123.40	(2,602.2	)	$	72,521.20
	Trading gains, net	$	248.4	(3.5	)	$	244.9			$	205.7	(4.1	)	$	201.6
	Total revenues	$	69,260.60	(1,301.3	)	$	67,959.30			$	75,497.60	(2,606.3	)	$	72,891.30
	Cost of sales of physical commodities	$	68,802.90	(1,297.8	)	$	67,505.10			$	75,074.40	(2,602.2	)	$	72,472.20
	Operating revenues	$	457.7	(3.5	)	$	454.2			$	423.2	(4.1	)	$	419.1
	Net operating revenues	$	309.7	(3.5	)	$	306.2			$	312.3	(4.1	)	$	308.2
	Income from continuing operations, before tax	$	19.3	(3.5	)	$	15.8			$	59.5	(4.1	)	$	55.4
	Income tax expense	$	4.4	(1.3	)	$	3.1			$	22.5	(1.6	)	$	20.9
	Net income attributable to INTL FCStone Inc. common stockholders	$	15	(2.2	)	$	12.8			$	37.3	(2.5	)	$	34.8
	Comprehensive income	$	18.7	(2.2	)	$	16.5			$	34.3	(2.5	)	$	31.8
	Basic earnings per share	$	0.79	(0.12	)	$	0.67			$	2.07	(0.14	)	$	1.93
	Diluted earnings per share	$	0.75	(0.11	)	$	0.64			$	1.96	(0.13	)	$	1.83

Earnings_per_Share_Tables

Earnings per Share (Tables)	12 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Schedule of Calculation of Numerator and Denominator in Earnings Per Share [Table Text Block]	'
	The following is a reconciliation of the numerator and denominator of the diluted net income per share computations for the periods presented below.
		Year Ended September 30,
	(in millions, except share amounts)	2013			2012			2011
					(As Restated)			(As Restated)
	Numerator:
	Income from continuing operations attributable to INTL FCStone Inc. stockholders	$	19.3		$	12.8		$	34.6
	Less: Allocation to participating securities	(0.8		)	(0.5		)	(0.9		)
	Income from continuing operations allocated to common stockholders	$	18.5		$	12.3		$	33.7
	Income from discontinued operations	$	—		$	—		$	0.2
	Less: Allocation to participating securities	—			—			—
	Income from discontinued operations allocated to common stockholders	$	—		$	—		$	0.2
	Diluted net income	$	19.3		$	12.8		$	34.8
	Less: Allocation to participating securities	(0.8		)	(0.5		)	(0.9		)
	Diluted net income allocated to common stockholders	$	18.5		$	12.3		$	33.9
	Denominator:
	Weighted average number of:
	Common shares outstanding	18,443,233			18,282,939			17,618,085
	Dilutive potential common shares outstanding:
	Share-based awards	625,264			873,960			949,369
	Diluted weighted-average shares	19,068,497			19,156,899			18,567,454

Assets_and_Liabilities_at_Fair1

Assets and Liabilities, at Fair Value (Tables)	12 Months Ended
	Sep. 30, 2013
Assets and Liabilities, at Fair Value [Abstract]	'
Fair Value, Assets Measured on Recurring Basis [Table Text Block]	'
		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
	U.S. government obligations	—			—			—			—			—
	Derivatives	1.8			0.2			—			(15.1		)	(13.1		)
	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 are included in that level.
		September 30, 2012
	(in millions)	Level 1			Level 2			Level 3			Netting and			Total
											Collateral
											-1
	Assets:
	Money market funds	$	0.1		$	—		$	—		$	—		$	0.1
	Certificate of deposits	10.4			—			—			—			10.4
	Unrestricted cash equivalents	10.5			—			—			—			10.5
	Commodities warehouse receipts	22.3			—			—			—			22.3
	U.S. government obligations	—			50.5			—			—			50.5
	Securities and other assets segregated under federal and other regulations	22.3			50.5			—			—			72.8
	Money market funds	335.1			—			—			—			335.1
	U.S. government obligations	—			1,318.30			—			—			1,318.30
	Mortgage-backed securities	—			7			—			—			7
	Derivatives	3,344.30			—			—			(3,494.7		)	(150.4		)
	Deposits and receivables from exchange-clearing organizations	3,679.40			1,325.30			—			(3,494.7		)	1,510.00
	Derivatives	0.7			5			—			(6.4		)	(0.7		)
	Deposits and receivables from broker-dealers, clearing organizations and counterparties - derivatives	0.7			5			—			(6.4		)	(0.7		)
	Common and preferred stock and American Depositary Receipts (“ADRs”)	17.8			5.6			0.9			—			24.3
	Exchangeable foreign ordinary equities and ADRs	10			—			—			—			10
	Corporate and municipal bonds	0.3			0.6			3.6			—			4.5
U.S. government obligations	—			0.3			—			—			0.3
Foreign government obligations	14.8			—			—			—			14.8
Derivatives	315.6			785.3			—			(1,047.0		)	53.9
Commodities leases	—			135.2			—			(93.1		)	42.1
Commodities warehouse receipts	7.5			—			—			—			7.5
Exchange firm common stock	3.4			9			—			—			12.4
Mutual funds and other	1.9			—			—			—			1.9
Financial instruments owned	371.3			936			4.5			(1,140.1		)	171.7
Total assets at fair value	$	4,084.20		$	2,316.80		$	4.5		$	(4,641.2	)	$	1,764.30
Liabilities:
Accounts payable and other accrued liabilities - contingent liabilities	$	—		$	—		$	14.8		$	—		$	14.8
Payable to customers - derivatives	3,562.30			—			—			(3,562.3		)	—
Common and preferred stock and ADRs	16.4			5.9			—			—			22.3
Exchangeable foreign ordinary equities and ADRs	5.7			—			—			—			5.7
Derivatives	338.1			775.2			—			(1,068.7		)	44.6
Commodities leases	—			220			—			(117.2		)	102.8
Financial instruments sold, not yet purchased	360.2			1,001.10			—			(1,185.9		)	175.4
Total liabilities at fair value	$	3,922.50		$	1,001.10		$	14.8		$	(4,748.2	)	$	190.2
-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 are included in that level.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	'
	The Company’s financial assets at fair value classified within level 3 of the fair value hierarchy as of September 30, 2013 and 2012 are summarized below:
	(in millions)	September 30, 2013			September 30, 2012
	Total level 3 assets	$	4.2		$	4.5
	Level 3 assets for which the Company bears economic exposure	$	4.2		$	4.5
	Total assets	$	2,848.00		$	2,953.00
	Total financial assets at fair value	$	1,627.70		$	1,764.30
	Total level 3 assets as a percentage of total assets	0.1		%	0.2		%
	Level 3 assets for which the Company bears economic exposure as a percentage of total assets	0.1		%	0.2		%
	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 fiscal years ended September 30, 2013 and 2012, including a summary of unrealized gains (losses) during the fiscal year ended on the Company’s level 3 financial assets and liabilities still held as of September 30, 2013.
		Level 3 Financial Assets and Financial Liabilities
		For the Year Ended September 30, 2013
	(in millions)	Balances at			Realized gains			Unrealized			Purchases/			Settlements			Transfers in		Balances at
		beginning of			(losses) during			gains (losses)			issuances						or (out) of		end of period
		period			period			during period									Level 3
	Assets:
	Common and preferred stock and ADRs	$	0.9		$	—		$	(0.2	)	$	—		$	—		$	—	$	0.7
	Corporate and municipal bonds	3.6			—			(0.1		)	—			—			—		3.5
		$	4.5		$	—		$	(0.3	)	$	—		$	—		$	—	$	4.2
	Liabilities:
	Contingent liabilities	$	14.8		$	—		$	2.6		$	5.6		$	(13.4	)	$	—	$	9.6
		Level 3 Financial Assets and Financial Liabilities
		For the Year Ended September 30, 2012
	(in millions)	Balances at			Realized gains			Unrealized			Purchases/			Settlements			Transfers in		Balances at
		beginning of			(losses) during			gains (losses)			issuances						or (out) of		end of period
		period			period			during period									Level 3
	Assets:
	Common and preferred stock and ADRs	$	1.1		$	—		$	(0.2	)	$	—		$	—		$	—	$	0.9
	Corporate and municipal bonds	3.6			—			—			—			—			—		3.6
	Mutual funds and other	0.4			(0.4		)	—			—			—			—		—
		$	5.1		$	(0.4	)	$	(0.2	)	$	—		$	—		$	—	$	4.5
	Liabilities:
	Contingent liabilities	$	22.3		$	—		$	2		$	0.1		$	(9.6	)	$	—	$	14.8
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	'
	The following tables summarize the Company’s pension assets, excluding cash held in the plan, by major category of plan assets measured at fair value on a recurring basis (at least annually) as of September 30, 2013 and 2012. For additional information and a detailed description of each level within the fair value hierarchy, see Note 4.
		September 30, 2013
	(in millions)	Level 1			Level 2			Level 3			Total
	Assets:
	Cash equivalents	$	—		$	0.5		$	—		$	0.5
	Fixed income:
	Government and agencies	—			0.6			—			0.6
	Collective funds:
	Fixed income	—			8.1			—			8.1
	Equities	—			18.7			—			18.7
	Real estate	—			1			—			1
	Total	$	—		$	28.9		$	—		$	28.9
		September 30, 2012
	(in millions)	Level 1			Level 2			Level 3			Total
	Assets:
	Cash equivalents	$	—		$	0.4		$	—		$	0.4
	Fixed income:
	Government and agencies	—			0.8			—			0.8
	Collective funds:
	Fixed income	—			7.7			—			7.7
	Equities	—			16.6			—			16.6
	Real estate	—			1			—			1
	Total	$	—		$	26.5		$	—		$	26.5
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 September 30, 2013 and September 30, 2012:
	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, is less than 0.1 million.
	September 30, 2012
	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	$	1,298.90		$	—		$	—		$	1,298.90
	Mortgage-backed securities	6.8			0.1			—			6.9
		$	1,305.70		$	0.1		$	—		$	1,305.80
	-1	Unrealized gain/loss on U.S. government obligations as of September 30, 2012, is less than 0.1 million.
	As of September 30, 2013 and September 30, 2012, investments in debt securities classified as available-for-sale (AFS) mature as follows:
	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
	September 30, 2012
		Due in						Estimated
	(in millions)	Less than 1 year			1 year or more			Fair Value
	U.S. government obligations	$	1,298.90		$	—		$	1,298.90
	Mortgage-backed securities	—			6.9			6.9
		$	1,298.90		$	6.9		$	1,305.80

Financial_Instruments_with_Off1

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk (Tables)	12 Months Ended
	Sep. 30, 2013
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk [Abstract]	'
Schedule of Derivative Instruments [Table Text Block]	'
		September 30, 2013						September 30, 2012
	(in millions)	Assets (1)			Liabilities (1)			Assets (1)			Liabilities (1)
	Derivative contracts not accounted for as hedges:
	Exchange-traded commodity derivatives	$	2,036.60		$	2,046.30		$	3,325.60		$	3,565.30
	OTC commodity derivatives	481.4			484.9			823.6			841.4
	Exchange-traded foreign exchange derivatives	89.3			104.2			63			47.7
	OTC foreign exchange derivatives	132.3			162.3			215.4			196.6
	Exchange-traded interest rate derivatives	4.3			36			0.9			2.6
	OTC interest rate derivatives	—			—			1.6			—
	Equity index derivatives	135.5			141.7			20.8			22
	Gross fair value of derivative contracts	2,879.40			2,975.40			4,450.90			4,675.60
	Impact of netting and collateral	(2,940.4		)	(2,944.7		)	(4,548.1		)	(4,631.0		)
	Total fair value included in ‘Deposits and receivables from exchange-clearing organizations’	$	(69.8	)				$	(150.4	)
	Total fair value included in ‘Deposits and receivables from broker-dealers, clearing organizations and counterparties’	$	(13.1	)				$	(0.7	)
	Total fair value included in ‘Financial instruments owned, at fair value’	$	21.9					$	53.9
	Fair value included in ‘Financial instruments sold, not yet purchased, at fair value’				$	30.7					$	44.6
	-1	As of September 30, 2013 and 2012, the Company’s derivative contract volume for open positions was approximately 4.1 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 net gains (losses) related to derivative financial instruments for the fiscal years ended September 30, 2013, 2012 and 2011, in accordance with the Derivatives and Hedging Topic of the ASC. The net gains (losses) set forth below are included in ‘trading gains, net’ in the consolidated income statements.
		Year Ended September 30,
	(in millions)	2013			2012			2011
					(As Restated)			(As Restated)
	Commodities	$	84.6		$	62.3		$	32.8
	Foreign exchange	11.6			10.4			15
	Interest rate	0.1			1.4			3.5
	Net gains from derivative contracts	$	96.3		$	74.1		$	51.3

Receivables_from_customers_net1

Receivables from customers, net and notes receivable, net (Tables)	12 Months Ended
	Sep. 30, 2013
Receivables from customers and notes receivable, net [Abstract]	'
Allowance for Credit Losses on Financing Receivables [Table Text Block]	'
	Activity in the allowance for doubtful accounts and notes for the years ended September 30, 2013, 2012 and 2011 was as follows:
	(in millions)	2013		2012			2011
	Balance, beginning of year	$	1	$	11.9		$	119.2
	Provision for bad debts	0.2		0.4			7.2
	Transfer in (1)	—		—			2.5
	Deductions:
	Charge-offs	—		(11.2		)	(113.3		)
	Recoveries	—		(0.1		)	(3.7		)
	Balance, end of year	$	1.2	$	1		$	11.9
	-1	During the three months ended December 31, 2010, certain open position derivative contracts, which had a $2.5 million credit reserve as of September 30, 2010 were closed, and the deficit account balance was reclassified from financial instruments owned to a receivable from customer. Accordingly, the previously established credit reserve amount was transferred into the allowance for doubtful accounts during the three months ended December 31, 2010.

Physical_Commodities_Inventory1

Physical Commodities Inventory (Tables)	12 Months Ended
	Sep. 30, 2013
Physical Commodities Inventory [Abstract]	'
Schedule of Inventory, Current [Table Text Block]	'
	The carrying values of the Company’s inventory as of September 30, 2013 and 2012 are shown below.
	(in millions)	September 30,		September 30, 2012
		2013
	Commodities in process	$	—	$	13.6
	Finished commodities	59		118
	Physical commodities inventory	$	59	$	131.6

Property_and_Equipment_net_Tab

Property and Equipment, net (Tables)	12 Months Ended
	Sep. 30, 2013
Property and Equipment, net [Abstract]	'
Property, Plant and Equipment [Table Text Block]	'
	A summary of property and equipment, at cost less accumulated depreciation as of September 30, 2013 and 2012 is as follows:
	(in millions)	September 30, 2013			September 30, 2012
	Property and equipment:
	Furniture and fixtures	$	6		$	6.3
	Software	6			3.9
	Equipment	10.2			9.3
	Leasehold improvements	9.6			9
	Total property and equipment	31.8			28.5
	Less accumulated depreciation	(14.3		)	(9.6		)
	Property and equipment, net	$	17.5		$	18.9

Goodwill_Tables

Goodwill (Tables)	12 Months Ended
	Sep. 30, 2013
Goodwill [Abstract]	'
Schedule of Goodwill [Table Text Block]	'
	Goodwill allocated to the Company’s operating segments as of September 30, 2013 and 2012 is as follows:
	(in millions)	September 30,		September 30,
		2013		2012
				(As Restated)
	Commodity and Risk Management Services	$	33.1	$	33.1
	Foreign Exchange	6.3		6.3
	Securities	8.1		5.3
	Goodwill	$	47.5	$	44.7

Intangible_Assets_Tables

Intangible Assets (Tables)	12 Months Ended
	Sep. 30, 2013
Intangible Assets [Abstract]	'
Schedule of Finite and Indefinite-Lived Intangible Assets [Table Text Block]	'
	Intangible assets of $2.8 million, attributed to customer relationships, acquired during the fiscal year ended September 30, 2013 relate to an acquisition, as discussed in Note 19.
	The gross and net carrying values of intangible assets as of the balance sheet dates, by major intangible asset class are as follows:
		September 30, 2013							September 30, 2012
	(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	)	$	—	$	3.7	$	(3.0	)	$	0.7
	Trade name	0.7		(0.7		)	—		0.7		(0.5		)	0.2
	Software programs/platforms	2.2		(1.5		)	0.7		2.2		(1.0		)	1.2
	Customer base	12.4		(2.6		)	9.8		9.6		(1.8		)	7.8
		19		(8.5		)	10.5		16.2		(6.3		)	9.9
	Intangible assets not subject to amortization
	Trade name	1.1		—			1.1		1.2		—			1.2
	Total intangible assets	$	20.1	$	(8.5	)	$	11.6	$	17.4	$	(6.3	)	$	11.1
Schedule of Expected Amortization Expense [Table Text Block]	'
	Amortization expense related to intangible assets was $2.2 million, $2.5 million, and $2.3 million for the fiscal years ended 2013, 2012 and 2011, respectively.
	As of September 30, 2013, the estimated future amortization expense was as follows:
	(in millions)
	Fiscal 2014	$	1.4
	Fiscal 2015	1
	Fiscal 2016	0.7
	Fiscal 2017	0.7
	Fiscal 2018	0.7
	Fiscal 2019 and thereafter	6
		$	10.5

Credit_Facilities_Tables

Credit Facilities (Tables)	12 Months Ended
	Sep. 30, 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 September 30, 2013 on the facilities, and outstanding borrowings on the facilities as well as indebtedness on senior notes as of September 30, 2013 and 2012:
	(in millions)
	Credit Facilities						Amounts Outstanding
		Borrower	Security	Renewal / Expiration Date	Total		September 30,		September 30,
					Commitment		2013		2012
		INTL FCStone Inc.	Certain pledged shares	September 20, 2016	$	140	$	55	$	48
		FCStone, LLC	None	April 10, 2014	75		—		20
		FCStone Merchants	Certain commodities assets	May 1, 2014	75		6		43.2
		INTL Commodities	Certain commodities assets	Expired July 31, 2013	—		—		107
					$	290	61		218.2
	Senior Unsecured Notes
		8.50% senior notes, due July 30, 2020					45.5		—
	Total indebtedness						$	106.5	$	218.2

Commitments_and_Contingencies_1

Commitments and Contingencies Future Minimum Lease Commitments (Tables)	12 Months Ended
	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	'
	Future aggregate minimum lease payments under noncancelable operating leases as of September 30, 2013 are as follows:
	(in millions)
	Year ending September 30,
	2014	$	6.7
	2015	5.8
	2016	4.5
	2017	4
	2018	3.7
	Thereafter	10.2
		$	34.9

Regulatory_Requirements_and_Su1

Regulatory Requirements and Subsidiary Dividend Restrictions (Tables)	12 Months Ended
	Sep. 30, 2013
Capital and Other Regulatory Requirements [Abstract]	'
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]	'
	All subsidiaries of the Company are in compliance with all of their regulatory requirements as of September 30, 2013, as follows:
	(in millions)				As of September 30, 2013
	Subsidiary	Regulatory Authority		Requirement Type	Actual		Minimum
							Requirement
	FCStone, LLC	CFTC		Net capital	$	106.3	$	66.3
	FCStone, LLC	CFTC		Segregated funds	$	1,693.50	$	1,669.60
	FCStone, LLC	CFTC		Secured funds	$	82.5	$	59.8
	INTL FCStone Ltd	FCA (United Kingdom)		Net capital	$	60.8	$	23.4
	INTL FCStone Ltd	FCA United Kingdom		Segregated funds	$	61.2	$	61.1
	INTL Global Currencies Limited	FCA (United Kingdom)		Net capital	$	11.4	$	1.2
	INTL FCStone Securities Inc.	SEC		Net capital	$	5	$	1
	FCC Investments, Inc.	SEC		Net capital	$	0.3	$	0.3
	FCStone Australia	Australian Securities and Investment Commission		Net capital	$	1.8	$	0.9
	FCStone Australia	New Zealand Clearing Ltd		Capital adequacy	$	11.6	$	4.1
	FCStone Commodity Services (Europe), Ltd	Central Bank of Ireland		Net capital	$	2	$	0.6
	INTL FCStone DTVM Ltda.	Brazilian Central Bank and Securities and Exchange Commission of Brazil		Capital adequacy	$	0.7	$	0.7
	INTL Capital S.A.	Rosario Futures Exchange (Argentina)		Capital adequacy	$	6.3	$	0.1
	INTL Capital S.A.	General Inspector of Justice (Argentina)		Net capital	$	8.5	$	6.4
	INTL Capital S.A.	Superintendent of Securities Markets of Buenos Aires (Argentina)		Net capital	$	4	$	0.3
Schedule of Regulatory Assets [Table Text Block]	'
	Funds deposited by customers and other assets, which have been segregated as belonging to the commodity customers as of September 30, 2013 and 2012, are as follows:
	(in millions)	September 30, 2013			September 30, 2012
	Cash, at banks - segregated	$	247.6		$	225.6
	Securities - customer segregated	—			—
	Securities held for customers in lieu of cash, at banks	19.5			47.2
	Deposits with and receivables from:
	Exchange-clearing organizations, including securities, net of omnibus eliminations	1,413.30			1,370.40
	Securities held for customers in lieu of cash	13.1			22.3
	Total customer-segregated funds	1,693.50			1,665.50
	Amount required to be segregated	1,669.60			1,620.50
	Excess funds in segregation	$	23.9		$	45
	Funds deposited by customers and other assets, which are held in separate accounts for customers trading foreign futures and foreign options customers, as of September 30, 2013 and 2012 are as follows:
	(in millions)	September 30, 2013			September 30, 2012
	Cash - secured	$	34.2		$	25.2
	Securities	—			3.3
	Equities with futures commission merchants	27			9.9
	Amounts held by clearing organizations of foreign boards of trade	—			20.8
	Amounts held by members of foreign boards of trade	21.3			30.1
	Total customer-secured funds	82.5			89.3
	Amount required to be secured	59.8			77.6
	Excess secured funds	$	22.7		$	11.7

ShareBased_Compensation_Tables

Share-Based Compensation (Tables)	12 Months Ended
	Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	'
	Fair value is estimated at the grant date based on a Black-Scholes-Merton option-pricing model using the following weighted-average assumptions:
		Year Ended September 30,
		2013			2012		2011
	Expected stock price volatility	35	%		57	%	77	%
	Expected dividend yield	—	%		—	%	—	%
	Risk free interest rate	0.37	%		1.53	%	0.72	%
	Average expected life (in years)	2.88			7.86		2.94
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	'
	The following is a summary of stock option activity for the year ended September 30, 2013:
		Shares			Number of		Weighted		Weighted				Weighted	Aggregate
		Available for			Options		Average		Average				Average	Intrinsic
		Grant			Outstanding		Exercise Price		Grant Date				Remaining	Value
									Fair Value				Term	($ millions)
													(in years)
	Balances at September 30, 2012	921,412			1,890,634		$	23.36	$	11.11			5.45	$	6
	Additional shares authorized by shareholders	1,000,000
	Termination of 2003 plan	(821,412	)
	Granted	(100,000	)		100,000		$	17.53	$	4.21
	Exercised				(177,246	)	$	8.4	$	5.26
	Forfeited	—			(32,738	)	$	10.35	$	3.88
	Expired	—			(667	)	$	23.49	$	11.58
	Balances at September 30, 2013	1,000,000			1,779,983		$	24.76	$	11.44			4.87	$	4.8
	Exercisable at September 30, 2013				680,820		$	27.47	$	11.04			1.91	$	3.1
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]	'
	The options outstanding as of September 30, 2013 broken down by exercise price are as follows:
	Exercise Price							Number of Options Outstanding	Weighted Average Exercise Price				Weighted Average Remaining Term
													(in Years)
	$	—		-	$	5		—		n/a			n/a
	$	5		-	$	10		301,875	$	7.02			1.18
	$	10		-	$	15		—		n/a			n/a
	$	15		-	$	20		322,179	$	18.01			2.4
	$	20		-	$	25		126,204	$	23.52			3.1
	$	25		-	$	30		800,000	$	25.91			8.22
	$	30		-	$	35		—		n/a			n/a
	$	35		-	$	40		—		n/a			n/a
	$	40		-	$	45		—		n/a			n/a
	$	45		-	$	50		—		n/a			n/a
	$	50		-	$	55		229,725	$	54.23			2.45
								1,779,983	$	24.76			4.87
Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]	'
	The following is a summary of restricted stock activity through September 30, 2013:
		Shares			Number of		Weighted		Weighted		Aggregate
		Available for			Shares		Average		Average		Intrinsic Value
		Grant			Outstanding		Grant Date		Remaining		($ millions)
							Fair Value		Term
									(in years)
	Balances at September 30, 2012	1,420,114			512,124		$	22.09	1.81		$	9.8
	Granted	(268,885	)		268,885		$	17.92
	Vested				(406,901	)	$	20.72
	Forfeited	3,633			(10,470	)	$	22.62
	Balances at September 30, 2013	1,154,862			363,638		$	20.53	1.74		$	7.4

Retirement_Plans_Retirement_Pl

Retirement Plans Retirement Plans (Tables)	12 Months Ended
	Sep. 30, 2013
Compensation and Retirement Disclosure [Abstract]	'
Schedule of Changes in Fair Value of Plan Assets [Table Text Block]	'
	The following table presents changes in, and components of, the Company’s net liability for retirement costs as of and for the years ended September 30, 2013, 2012 and 2011, based on measurement dates of September 30, 2013, 2012 and 2011, respectively:
	(in millions)	September 30, 2013			September 30, 2012			September 30, 2011
	Changes in benefit obligation:
	Benefit obligation, beginning of year	$	42.8		$	39		$	37.6
	Interest cost	1.5			1.8			1.9
	Actuarial loss	(2.6		)	5.8			2.6
	Benefits paid	(4.2		)	(3.8		)	(3.1		)
	Benefit obligation, end of year	37.5			42.8			39
	Changes in plan assets:
	Fair value, beginning of year	26.5			24.2			24.2
	Actual return	3.7			4.6			(0.4		)
	Employer contribution	2.9			1.5			3.5
	Benefits paid	(4.2		)	(3.8		)	(3.1		)
	Fair value, end of year	28.9			26.5			24.2
	Funded status	$	(8.6	)	$	(16.3	)	$	(14.8	)
Schedule of Accumulated and Projected Benefit Obligations [Table Text Block]	'
	The following table displays the Company’s defined benefit plans that have accumulated benefit obligations and projected benefit obligations in excess of the fair value of plans assets (underfunded ABO) as of September 30, 2013 and 2012:
	(in millions)	September 30, 2013			September 30, 2012
	Accumulated benefit obligations	$	37.5		$	42.8
	Projected benefit obligations	$	37.5		$	42.8
	Plan assets	$	28.9		$	26.5
Schedule of Assumptions Used [Table Text Block]	'
	The following weighted-average assumptions were used to determine net periodic pension cost for the years ended September 30, 2013, 2012 and 2011:
		Year Ended September 30,
		2013		2012	2011
	Weighted average assumptions:
	Discount rate	3.80%		4.80%	5.30%
	Expected return on assets	7.00%		7.30%	7.30%
	The following weighted-average assumptions were used to determine benefit obligations in the accompanying consolidated balance sheets as of September 30, 2013 and 2012:
		September 30, 2013		September 30, 2012
	Weighted average assumptions:
	Discount rate	4.60%		3.80%
	Expected return on assets	7.00%		7.00%
Schedule of Net Benefit Costs [Table Text Block]	'
	The components of net periodic pension cost recognized in the consolidated income statements for the years ended September 30, 2013, 2012 and 2011 were as follows:
		Year Ended September 30,
	(in millions)	2013			2012			2011
	Interest cost	$	1.5		$	1.8		$	1.9
	Less expected return on assets	(1.8		)	(1.7		)	(1.7		)
	Net amortization and deferral	0.8			0.4			—
	Net periodic pension cost	$	0.5		$	0.5		$	0.2
Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]	'
	Other changes in plan assets and benefit obligations recognized in other comprehensive income for the years ended September 30, 2013 and 2012 were as follows:
		Year Ended September 30,
	(in millions)	2013			2012
	Net (gain) loss	$	(4.6	)	$	2.9
	Amortization of loss	(0.8		)	(0.4		)
	Total recognized in other comprehensive income	(5.4		)	2.5
	Total recognized in net periodic benefit cost and other comprehensive income	$	(4.9	)	$	3
Schedule of Allocation of Plan Assets [Table Text Block]	'
	The following table sets forth the actual asset allocation as of September 30, 2013 and 2012, and the target asset allocation for the Company’s plan assets:
		September 30, 2013		September 30, 2012	Target Asset Allocation
	Equity securities	68%		66%	70%
	Debt securities	32%		34%	30%
	Total	100%		100%
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	'
	The following tables summarize the Company’s pension assets, excluding cash held in the plan, by major category of plan assets measured at fair value on a recurring basis (at least annually) as of September 30, 2013 and 2012. For additional information and a detailed description of each level within the fair value hierarchy, see Note 4.
		September 30, 2013
	(in millions)	Level 1			Level 2			Level 3			Total
	Assets:
	Cash equivalents	$	—		$	0.5		$	—		$	0.5
	Fixed income:
	Government and agencies	—			0.6			—			0.6
	Collective funds:
	Fixed income	—			8.1			—			8.1
	Equities	—			18.7			—			18.7
	Real estate	—			1			—			1
	Total	$	—		$	28.9		$	—		$	28.9
		September 30, 2012
	(in millions)	Level 1			Level 2			Level 3			Total
	Assets:
	Cash equivalents	$	—		$	0.4		$	—		$	0.4
	Fixed income:
	Government and agencies	—			0.8			—			0.8
	Collective funds:
	Fixed income	—			7.7			—			7.7
	Equities	—			16.6			—			16.6
	Real estate	—			1			—			1
	Total	$	—		$	26.5		$	—		$	26.5
Schedule of Expected Benefit Payments [Table Text Block]	'
	The following benefit payments, which reflect expected future service, are expected to be paid:
	(in millions)
	Year ending September 30,
	2014	$	3.6
	2015	3.3
	2016	3.2
	2017	2.9
	2018	1.9
	2019 - 2023	9.5
		$	24.4

Other_Expenses_Tables

Other Expenses (Tables)	12 Months Ended
	Sep. 30, 2013
Other Expenses [Abstract]	'
Schedule of Other Operating Cost and Expense, by Component [Table Text Block]	'
	Other expenses for the years ended September 30, 2013, 2012 and 2011 are comprised of the following:
		Year Ended September 30,
	(in millions)	2013		2012		2011
	Contingent consideration, net(1)	3		2.9		4.7
	Insurance	1.8		1.7		1.5
	Advertising, meetings and conferences	2.3		2.5		1.8
	Non-trading hardware and software maintenance and software licensing	2.7		2.2		2.8
	Office supplies and printing	1.2		1.3		1.1
	Other clearing related expenses	1.6		1.7		1.8
	Other non-income taxes	3.8		4		2.8
	Other	6.8		5.3		4.9
	Total other expenses	$	23.2	$	21.6	$	21.4
	(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 4) and additional purchase price, based on achieving specific conditions and earnings targets, relating to FCStone, LLC’s previous acquisitions of Downes O’Neill, LLC (“Downes O’Neill”) and Globecot, Inc. (“Globecot”). When the Downes O’Neill and Globecot acquisitions occurred, they were recorded in accordance with SFAS No. 141, Business Combinations (“SFAS 141”). As a result of the FCStone transaction on September 30, 2009, these contingent purchase price amounts were considered pre-acquisition contingencies, which were not reasonably estimable during the merger allocation period following the FCStone transaction. In accordance with SFAS 141, adjustments to pre-acquisition contingencies, made after the end of the allocation period, are included in earnings in the current period. The final pre-acquisition contingency expense was recorded during fiscal year 2013 and there are no further contingent payments relating to the Downes O’Neill or Globecot acquisitions.

Income_Taxes_Income_Taxes_Tabl

Income Taxes Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	'
	The components of the provision for income taxes attributable to income from continuing operations were as follows:
		Year Ended September 30,
	(in millions)	2013				2012				2011
						(As Restated)				(As Restated)
	Current taxes:
	U.S. Federal	$	(1.2	)		$	(6.9	)		$	7.6
	U.S. State and local	(1.3		)		0.4				1.6
	International	13.5				10.1				9.9
	Total current taxes	11				3.6				19.1
	Deferred taxes	(7.7		)		(0.5		)		1.8
	Income tax expense	$	3.3			$	3.1			$	20.9
	Income tax expense (benefit) for the years ended September 30, 2013, 2012 and 2011 was allocated as follows:
		Year Ended September 30,
	(in millions)	2013				2012				2011
						(As Restated)				(As Restated)
	Income tax expense attributable to income from continuing operations	$	3.3			$	3.1			$	20.9
	Income tax expense attributable to loss from discontinued operations	—				—				0.1
	Taxes allocated to stockholders’ equity, related to unrealized gains (losses) on available-for-sale securities	(1.6		)		2.2				(0.3		)
	Taxes allocated to stockholders’ equity, related to pension liabilities	1.8				(1.0		)		(1.7		)
	Taxes allocated to stockholders’ equity, related to unrealized loss on derivatives	—				—				0.6
	Taxes allocated to additional paid-in capital, related to share-based compensation	—				(0.2		)		—
	Total income tax expense	$	3.5			$	4.1			$	19.6
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]	'
	U.S. and international components of (loss) income from continuing operations, before income taxes, was as follows:
		Year Ended September 30,
	(in millions)	2013				2012				2011
						(As Restated)				(As Restated)
	U.S.	$	(21.7	)		$	(17.2	)		$	23.2
	International	44.3				33				32.2
	Income from continuing operations, before tax	$	22.6			$	15.8			$	55.4
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	'
	Items accounting for the difference between income taxes computed at the federal statutory rate and the provision for income taxes were as follows:
		Year Ended September 30,
		2013			2012			2011
					(As Restated)			(As Restated)
	Federal statutory rate effect of:	35	%		35	%		35	%
	U.S. State and local income taxes	0.8	%		(2.0	)%		0.8	%
	Foreign earnings taxed at lower rates	(20.1	)%		(20.4	)%		(3.1	)%
	Change in foreign valuation allowance	(0.2	)%		2.2	%		0.7	%
	Change in state valuation allowance	(7.6	)%		(0.2	)%		1	%
	Tax impact of U.S. State and local rate change	(2.4	)%		—	%		1.2	%
	Uncertain tax positions	(0.3	)%		(1.5	)%		1.5	%
	Non-deductible meals and entertainment	1.3	%		2.7	%		—	%
	Foreign permanent items	4.3	%		6	%		—	%
	Other reconciling items	3.9	%		(4.2	)%		0.6	%
	Penalties	2.4	%		—	%		—	%
	Audit settlements	(1.7	)%		—	%		—	%
	Effective rate	15.4	%		17.6	%		37.7	%
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	'
	The components of deferred income tax assets and liabilities were as follows:
	(in millions)	September 30, 2013				September 30, 2012
						(As Restated)
	Deferred tax assets:
	Share-based compensation	$	2.7			$	2.5
	Pension liability	3.4				6.1
	Deferred compensation	2.3				3.2
	Foreign net operating loss carryforwards	1.9				2
	U.S. State and local net operating loss carryforwards	4.9				4.9
	U.S. Federal net operating loss carryforwards	7.3				—
	Intangible assets	6.9				6.1
	Capital loss carryforwards	0.7				1.1
	Bad debt reserve	0.2				0.1
	Foreign tax credit	0.1				0.3
	Other compensation	1.6				4.5
	Other	1.4				1.2
	Total gross deferred tax assets	33.4				32
	Less valuation allowance	(2.3		)		(4.1		)
	Deferred tax assets	31.1				27.9
	Deferred income tax liabilities:
	Unrealized gain on securities	1.3				3.1
	Prepaid expenses	0.9				1.1
	Fixed assets	3.4				3.8
	Deferred income tax liabilities	5.6				8
	Net deferred tax assets	$	25.5			$	19.9
Summary of Income Tax Contingencies [Table Text Block]	'
	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
		Year Ended September 30,
	(in millions)	2013				2012				2011
	Balance, beginning of year	$	0.5			$	0.9			$	—
	Gross increases for tax positions related to current year	0.1				—				—
	Gross increases for tax positions related to prior years	—				—				0.9
	Gross decreases for tax positions of prior years	(0.2		)		(0.1		)		—
	Settlements	(0.2		)		(0.1		)		—
	Lapse of statute of limitations	(0.1		)		(0.2		)		—
	Balance, end of year	$	0.1			$	0.5			$	0.9

Quarterly_Financial_Informatio1

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Sep. 30, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Schedule of Quarterly Financial Information [Table Text Block]	'
	The impact of the immaterial correction of the reconciliation errors and errors relating to certain intercompany physical sales, as previously discussed in Note 2, to the fiscal 2013 quarterly information is as follows:
		For the 2013 Fiscal Quarter Ended
	(in millions, except per share amounts)	September 30				30-Jun					31-Mar							31-Dec
						As Reported		As Revised			As Reported			As Revised				As Reported		As Revised
	Total revenues	$	9,030.40			$	11,039.50	$	9,996.60		$	13,113.10		$	12,188.50			$	12,719.50	$	12,552.80
	Cost of sales of physical commodities	8,917.80				10,917.40		9,873.80			12,995.80			12,071.20				12,593.80		12,427.10
	Operating revenues	112.6				122.1		122.8			117.3			117.3				125.7		125.7
	Transaction-based clearing expenses	28				28.9		28.9			28.6			28.6				24.6		24.6
	Introducing broker commissions	11.5				11		11			9.6			9.6				8.4		8.4
	Interest expense	2.9				3.2		3.2			2.9			2.9				3.5		3.5
	Net operating revenues	70.2				79		79.7			76.2			76.2				89.2		89.2
	Compensation and other expenses	72.7				74.9		74.8			74.8			74.8				70.4		70.4
	(Loss) income before tax	(2.5		)		4.1		4.9			1.4			1.4				18.8		18.8
	Income tax (benefit) expense	(3.7		)		1.3		1.6			(0.1		)	(0.1		)		5.5		5.5
	Net income	$	1.2			$	2.8	$	3.3		$	1.5		$	1.5			$	13.3	$	13.3
	Net basic earnings per share	$	0.05			$	0.15	$	0.18		$	0.08		$	0.08			$	0.7	$	0.7
	Net diluted earnings per share	$	0.04			$	0.15	$	0.17		$	0.08		$	0.08			$	0.68	$	0.68
	The impact of the restatement for the correction of the reconciliation errors and the immaterial correction of errors relating to certain intercompany physical sales, as previously discussed in Note 2, to the fiscal 2012 quarterly information is as follows:
		For the 2012 Fiscal Quarter Ended
	(in millions, except per share amounts)	30-Sep						30-Jun						31-Mar						31-Dec
		As Reported			As Restated			As Reported		As Restated				As Reported			As Restated			As Reported			As Restated
	Total revenues	$	17,668.10		$	17,369.10		$	17,351.10	$	17,192.90			$	16,951.00		$	16,808.00		$	17,290.40		$	16,589.30
	Cost of sales of physical commodities	17,550.10			17,251.20			17,227.30		17,071.40				16,831.40			16,689.50			17,194.10			16,493.00
	Operating revenues	118			117.9			123.8		121.5				119.6			118.5			96.3			96.3
	Transaction-based clearing expenses	26			26			30.3		30.3				26.9			26.9			22.2			22.2
	Introducing broker commissions	9.3			9.3			7.9		7.9				8			8			5.8			5.8
	Interest expense	3.3			3.3			2.6		2.6				3.6			3.6			2.1			2.1
	Net operating revenues	79.4			79.3			83		80.7				81.1			80			66.2			66.2
	Compensation and other expenses	68.9			68.9			77.1		77.1				77.5			77.5			66.9			66.9
	Income from continuing operations, before tax	10.5			10.4			5.9		3.6				3.6			2.5			(0.7		)	(0.7		)
	Income tax expense (benefit)	2.2			2.1			1.2		0.4				1.2			0.8			(0.2		)	(0.2		)
	Income (loss) from continuing operations	8.3			8.3			4.7		3.2				2.4			1.7			(0.5		)	(0.5		)
	Add: Net loss attributable to noncontrolling interests	—			—			—		—				—			—			0.1			0.1
	Net income (loss) attributable to INTL FCStone Inc. common stockholders	$	8.3		$	8.3		$	4.7	$	3.2			$	2.4		$	1.7		$	(0.4	)	$	(0.4	)
	Net basic earnings (loss) per share	$	0.44		$	0.44		$	0.24	$	0.16			$	0.13		$	0.09		$	(0.02	)	$	(0.02	)
	Net diluted earnings (loss) per share	$	0.42		$	0.42		$	0.23	$	0.15			$	0.12		$	0.09		$	(0.02	)	$	(0.02	)

Segment_and_Geographic_Informa1

Segment and Geographic Information (Tables)	12 Months Ended
	Sep. 30, 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:
		Year Ended September 30,
	(in millions)	2013		2012			2011
				(As Restated)			(As Restated)
	Total revenues:
	Commodity and Risk Management Services	$	43,218.20	$	67,627.00		$	72,667.80
	Foreign Exchange	66.9		62.6			59.3
	Securities	61.1		39.9			30.5
	Clearing and Execution Services	100.8		93.8			66.1
	Other	314.1		136.2			67.2
	Corporate unallocated	7.2		(0.2		)	0.4
	Total	$	43,768.30	$	67,959.30		$	72,891.30
	Operating revenues (loss):
	Commodity and Risk Management Services	$	221.7	$	242.5		$	248.5
	Foreign Exchange	66.9		62.6			59.3
	Securities	61.1		39.9			30.5
	Clearing and Execution Services	100.8		93.8			66.1
	Other	20.7		15.6			14.3
	Corporate unallocated	7.2		(0.2		)	0.4
	Total	$	478.4	$	454.2		$	419.1
	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	$	131.1	$	139.5		$	147.5
	Foreign Exchange	44		41.3			37.1
	Securities	30.5		19.8			16.5
	Clearing and Execution Services	15.3		14.3			14.3
	Other	13.2		10.3			10
	Total	$	234.1	$	225.2		$	225.4
	Segment income:
	(Net contribution less non-variable direct segment costs):
	Commodity and Risk Management Services	$	59.6	$	66.2		$	89.4
	Foreign Exchange	29.8		28.3			28
	Securities	13.9		4.5			1.9
	Clearing and Execution Services	1.9		2.2			4.9
	Other	9.1		5.4			5.6
	Total	$	114.3	$	106.6		$	129.8
	Reconciliation of segment income to income from continuing operations, before tax:
	Segment income	$	114.3	$	106.6		$	129.8
	Costs not allocated to operating segments	91.7		90.8			74.4
	Income from continuing operations, before tax	$	22.6	$	15.8		$	55.4
	(in millions)	As of September 30, 2013		As of September 30, 2012			As of September 30, 2011
				(As Restated)			(As Restated)
	Total assets:
	Commodity and Risk Management Services	$	1,105.10	$	1,439.70		$	1,534.80
	Foreign Exchange	145		124.5			146.1
	Securities	198.5		88.7			104.8
	Clearing and Execution Services	1,246.40		1,090.90			734.4
	Other	37.3		110.8			43.4
	Corporate unallocated	115.7		98.4			68.5
	Total	$	2,848.00	$	2,953.00		$	2,632.00
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]	'
	Information regarding revenues and operating revenues for the years ended September 30, 2013, 2012 and 2011, and information regarding long-lived assets (defined as property, equipment, leasehold improvements and software) as of September 30, 2013, 2012 and 2011 in geographic areas were as follows:
		Year Ended September 30,
	(in millions)	2013		2012			2011
				(As Restated)			(As Restated)
	Total revenues:
	United States	$	29,062.00	$	53,398.00		$	48,165.30
	Europe	65.6		69.9			35.1
	South America	51.3		58.2			53.3
	Asia	14,582.10		14,420.80			24,627.00
	Other	7.3		12.4			10.6
	Total	$	43,768.30	$	67,959.30		$	72,891.30
	Operating revenues:
	United States	$	333.9	$	293.8		$	298
	Europe	65.6		69.9			35.1
	South America	51.3		58.2			53.3
	Asia	20.3		19.9			27.6
	Other	7.3		12.4			5.1
	Total	$	478.4	$	454.2		$	419.1
	(in millions)	As of September 30, 2013		As of September 30, 2012			As of September 30, 2011
	Long-lived assets, as defined:
	United States	$	9.1	$	11.5		$	10.7
	Europe	5.4		3.8			2
	South America	2.4		2.8			1.6
	Asia	0.5		0.7			0.6
	Other	0.1		0.1			0.1
	Total	$	17.5	$	18.9		$	15

Description_of_Business_and_Si2

Description of Business and Significant Accounting Policies Description of Business (Accounts, Customers and Other Facts) (Details)	12 Months Ended
	Sep. 30, 2013
Description of Business and Significant Accounting Policies [Abstract]	'
Number of different types of foreign currencies	130
Number of accounts for customers company-wide	20,000
Number of customers company-wide	11,000

Description_of_Business_and_Si3

Description of Business and Significant Accounting Policies Cash, Cash Equivalents, Securities (Details) (USD $)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash, Cash Equivalents, and Securities Disclosed in Significant Accounting Policies [Abstract]	'	'
Cash Held at Banks and Money Market Funds - Segregated	$416,800,000	$284,700,000
US Government Obligations and other securities	19,500,000	50,500,000
Commodities Warehouse Receipts	13,100,000	22,300,000
Cash and Cash Equivalents - Deposits and Receivables	1,000,000,000	400,000,000
US Government Securities and Other Securities - Deposits and Receivables	600,000,000	1,300,000,000
Gain (Loss) on Sale of Property Plant Equipment	900,000	'
Memberships in Exchanges Owned	10,400,000	10,500,000
Fair Value of Exchange Memberships	$8,500,000	$8,900,000

Description_of_Business_and_Si4

Description of Business and Significant Accounting Policies Notes Receivable - Participation (Details)	Sep. 30, 2013
Minimum [Member]	'
Short Term Notes Receivable Outstanding Balance Threshold, Percentage	90.00%
Maximum [Member]	'
Short Term Notes Receivable Outstanding Balance Threshold, Percentage	98.00%

Basis_of_Presentation_and_Cons

Basis of Presentation and Consolidation (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012
Basis of Presentation and Consolidation (Reclassifications) [Abstract]	'	'
Preferred Stock, Shares Outstanding	0	0
Preferred Stock, Par or Stated Value Per Share	$0.01	$0.01

Restatement_of_Previously_Issu2

Restatement of Previously Issued Financial Statements (Details) (USD $)	12 Months Ended			3 Months Ended								12 Months Ended			3 Months Ended	12 Months Ended		36 Months Ended		3 Months Ended							12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2010	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2012	Sep. 30, 2011
				As Reported [Member]	As Reported [Member]	As Reported [Member]	As Reported [Member]	As Reported [Member]	As Reported [Member]	As Reported [Member]	As Reported [Member]	As Reported [Member]	As Reported [Member]	Cumulative Prior Period Adjustments [Member]	FY 2012 Adjustment [Member]	FY 2012 Adjustment [Member]	FY 2012 Adjustment [Member]	FY 2012 Adjustment [Member]	FY 2012 Adjustment [Member]	As Restated [Member]	As Restated [Member]	As Restated [Member]	As Restated [Member]	As Restated [Member]	As Restated [Member]	As Restated [Member]	As Restated [Member]	As Restated [Member]
Receivables from Brokers-Dealers and Clearing Organizations	$168.30	$116.80	'	'	'	'	'	$127.40	'	'	'	$127.40	'	($7.10)	'	($3.50)	'	($3.50)	'	'	'	'	$116.80	'	'	'	$116.80	'
Income taxes receivable	15.5	15.5	'	'	'	'	'	11.9	'	'	'	11.9	'	2.3	'	1.3	'	1.3	'	'	'	'	15.5	'	'	'	15.5	'
Goodwill and intangible assets, net	59.1	55.8	'	'	'	'	'	54.7	'	'	'	54.7	'	1.1	'	0	'	0	'	'	'	'	55.8	'	'	'	55.8	'
Assets	2,848	2,953	2,632	'	'	'	'	2,958.90	'	'	'	2,958.90	'	-3.7	'	-2.2	'	-2.2	'	'	'	'	2,953	'	'	'	2,953	'
Liabilities	2,512.60	2,639.80	'	'	'	'	'	2,639.80	'	'	'	2,639.80	'	0	'	0	'	0	'	'	'	'	2,639.80	'	'	'	2,639.80	'
Retained earnings	125.4	106.1	'	'	'	'	'	112	'	'	'	112	'	-3.7	'	-2.2	'	-2.2	'	'	'	'	106.1	'	'	'	106.1	'
Total stockholders' equity	335.4	313.2	'	'	'	'	'	319.1	'	'	'	319.1	'	-3.7	'	-2.2	'	-2.2	1.2	'	'	'	313.2	'	'	'	313.2	'
Total liabilities and equity	2,848	2,953	'	'	'	'	'	2,958.90	'	'	'	2,958.90	'	-3.7	'	-2.2	'	-2.2	'	'	'	'	2,953	'	'	'	2,953	'
Sales of physical commodities	43,283.70	67,514.70	72,521.20	'	'	'	'	'	'	'	'	68,812.50	75,123.40	'	'	-1,297.80	-2,602.20	'	'	'	'	'	'	'	'	'	67,514.70	72,521.20
Trading gains, net	265	244.9	201.6	'	'	'	'	'	'	'	'	248.4	205.7	'	'	-3.5	-4.1	'	'	'	'	'	'	'	'	'	244.9	201.6
Total revenues	43,768.30	67,959.30	72,891.30	9,030.40	11,039.50	13,113.10	12,719.50	17,668.10	17,351.10	16,951	17,290.40	69,260.60	75,497.60	'	'	-1,301.30	-2,606.30	'	'	9,996.60	12,188.50	12,552.80	17,369.10	17,192.90	16,808	16,589.30	67,959.30	72,891.30
Cost of sales of physical commodities	43,289.90	67,505.10	72,472.20	8,917.80	10,917.40	12,995.80	12,593.80	17,550.10	17,227.30	16,831.40	17,194.10	68,802.90	75,074.40	'	'	-1,297.80	-2,602.20	'	'	9,873.80	12,071.20	12,427.10	17,251.20	17,071.40	16,689.50	16,493	67,505.10	72,472.20
Operating revenues	478.4	454.2	419.1	112.6	122.1	117.3	125.7	118	123.8	119.6	96.3	457.7	423.2	'	'	-3.5	-4.1	'	'	122.8	117.3	125.7	117.9	121.5	118.5	96.3	454.2	419.1
Net operating revenues	315.3	306.2	308.2	70.2	79	76.2	89.2	79.4	83	81.1	66.2	309.7	312.3	'	'	-3.5	-4.1	'	'	79.7	76.2	89.2	79.3	80.7	80	66.2	306.2	308.2
Income from continuing operations, before tax	22.6	15.8	55.4	-2.5	4.1	1.4	18.8	10.5	5.9	3.6	-0.7	19.3	59.5	'	'	-3.5	-4.1	'	'	4.9	1.4	18.8	10.4	3.6	2.5	-0.7	15.8	55.4
Income tax expense	3.3	3.1	20.9	-3.7	1.3	-0.1	5.5	2.2	1.2	1.2	-0.2	4.4	22.5	'	'	-1.3	-1.6	'	'	1.6	-0.1	5.5	2.1	0.4	0.8	-0.2	3.1	20.9
Net income attributable to INTL FCStone Inc. common stockholders	19.3	12.8	34.8	'	'	'	'	8.3	4.7	2.4	-0.4	15	37.3	'	0.5	-2.2	-2.5	5.9	'	'	'	'	8.3	3.2	1.7	-0.4	12.8	34.8
Comprehensive income	$15.10	$16.50	$31.80	'	'	'	'	'	'	'	'	$18.70	$34.30	'	'	($2.20)	($2.50)	'	'	'	'	'	'	'	'	'	$16.50	$31.80
Net basic earnings per share	$1.01	$0.67	$1.93	$0.05	$0.15	$0.08	$0.70	$0.44	$0.24	$0.13	($0.02)	$0.79	$2.07	'	'	($0.12)	($0.14)	'	'	$0.18	$0.08	$0.70	$0.44	$0.16	$0.09	($0.02)	$0.67	$1.93
Net diluted earnings per share	$0.97	$0.64	$1.83	$0.04	$0.15	$0.08	$0.68	$0.42	$0.23	$0.12	($0.02)	$0.75	$1.96	'	'	($0.11)	($0.13)	'	'	$0.17	$0.08	$0.68	$0.42	$0.15	$0.09	($0.02)	$0.64	$1.83

Earnings_per_Share_Antidulitiv

Earnings per Share - Antidulitive Securities (Details)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Earnings Per Share [Abstract]	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,447,688	1,157,601	386,031

Earnings_per_Share_EPS_Reconci

Earnings per Share - EPS Reconciliation (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Earnings Per Share [Abstract]	'	'	'
Income (Loss) from Continuing Operations Attributable to Parent	$19.30	$12.80	$34.60
Undistributed Earnings Allocated to Participating Securities - Continuing Ops	-0.8	-0.5	-0.9
Income from continuing operations allocated to common stockholders	18.5	12.3	33.7
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	0	0.2
Undistributed Earnings Allocated to Participating Securities - Disc Ops	0	0	0
Income from discontinued operations allocated to common stockholders	0	0	0.2
Net Income (Loss) Available to Common Stockholders, Diluted	19.3	12.8	34.8
Undistributed Earnings Allocated to Participating Securities	-0.8	-0.5	-0.9
Diluted net income allocated to common stockholders	$18.50	$12.30	$33.90
Weighted Average Number of Shares Outstanding, Basic	18,443,233	18,282,939	17,618,085
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]	'	'	'
Stock Options And Warrants For Diluted Earnings Per Share Calculation	625,264	873,960	949,369
Diluted weighted-average shares	19,068,497	19,156,899	18,567,454

Assets_and_Liabilities_at_Fair2

Assets and Liabilities, at Fair Value - Details of Level 3 Assets and Liabilities (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
In Millions, unless otherwise specified
Assets and Liabilities, at Fair Value [Abstract]	'	'	'
Assets	$2,848	$2,953	$2,632
Assets, Fair Value Disclosure	$1,627.70	$1,764.30	'
Total level 3 assets as a percentage of total assets	0.10%	0.20%	'
Level 3 assets for which the company bears economic exposure as a percertange of total assets	0.10%	0.20%	'
Total level 3 assets as a percentage of total financial assets at fair value	0.30%	0.30%	'

Assets_and_Liabilities_at_Fair3

Assets and Liabilities, at Fair Value - Rollforward of Level 3 (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Rollforward of Level 3 Securities [Roll Forward]	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$4.50	$5.10	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	-0.4	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	-0.3	-0.2	'
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	4.2	4.5	'
Contingent Consideration [Member]	'	'	'
Rollforward of Level 3 Liabilities [Roll Forward]	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	14.8	22.3	'
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)	2.6	2	3.1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	-13.4	-9.6	'
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	9.6	14.8	22.3
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	0.9	1.1	'
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)	-0.2	-0.2	'
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	3.6	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, 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	3.5	3.6	'
Mutual funds and other [Member]	'	'	'
Rollforward of Level 3 Securities [Roll Forward]	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	'	0.4	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	'	-0.4	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	'	0	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	'	0	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	'	0	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	'	$0	'

Assets_and_Liabilities_at_Fair4

Assets and Liabilities, at Fair Value - Financial Assets and Liabilities Measured at Fair Value (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$4.20	$4.50	$5.10
Cash and Securities Segregated under Federal and Other Regulations	449.4	357.5	'
Receivables from Clearing Organizations	1,576.60	1,619.80	'
Receivables from Brokers-Dealers and Clearing Organizations	168.3	116.8	'
Financial instruments, owned, at fair value	158.5	171.7	'
Equity Investments in Exchange Stock - Fair Value	4.4	12.4	'
Equity Investments in Exchange Stock - Cost	3.7	4.4	'
Assets, Fair Value Disclosure	1,627.70	1,764.30	'
Total Level 3 Assets	4.2	4.5	'
Accounts payable and other accrued liabilities	114	127	'
Payables to Customers	2,091.80	2,072.30	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	179.9	175.4	'
Derivative Liabilities	30.7	'	'
Level 3 assets for which the company bears economic exposure	4.2	4.5	'
Assets	2,848	2,953	2,632
Total level 3 assets as a percentage of total assets	0.10%	0.20%	'
Level 3 assets for which the company bears economic exposure as a percertange of total assets	0.10%	0.20%	'
Total level 3 assets as a percentage of total financial assets at fair value	0.30%	0.30%	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	-0.4	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	-0.3	-0.2	'
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, Purchases	0	0	'
Fair Value, Measurements, Recurring [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	3	10.5	'
Cash and Securities Segregated under Federal and Other Regulations	107.6	72.8	'
Receivables from Clearing Organizations	1,371.70	1,510	'
Financial instruments, owned, at fair value	158.5	171.7	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	'	175.4	'
Liabilities, Fair Value Disclosure	189.5	190.2	'
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 [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Accounts payable and other accrued liabilities	9.6	14.8	'
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, at fair value	6.1	42.1	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	41	102.8	'
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, at fair value	7.7	14.8	'
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, at fair value	69.8	24.3	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	99.5	22.3	'
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, at fair value	3.6	4.5	'
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, at fair value	0.3	0.3	'
Fair Value, Measurements, Recurring [Member] | Derivative [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Financial instruments, owned, at fair value	21.9	53.9	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	'	44.6	'
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, at fair value	4	7.5	'
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, at fair value	36.7	10	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	8.7	5.7	'
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, at fair value	4	1.9	'
Fair Value, Measurements, Recurring [Member] | Derivative [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Receivables from Brokers-Dealers and Clearing Organizations	-13.1	-0.7	'
Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Receivables from Clearing Organizations	841.4	335.1	'
Fair Value, Measurements, Recurring [Member] | US Government Debt Securities [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Receivables from Clearing Organizations	594.8	1,318.30	'
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Receivables from Clearing Organizations	5.3	7	'
Fair Value, Measurements, Recurring [Member] | Derivative [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Receivables from Clearing Organizations	-69.8	-150.4	'
Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Cash and Securities 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]	'	'	'
Cash and Securities Segregated under Federal and Other Regulations	13.1	22.3	'
Fair Value, Measurements, Recurring [Member] | US Government Debt Securities [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Cash and Securities Segregated under Federal and Other Regulations	19.5	50.5	'
Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	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]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	2.9	10.4	'
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	3	10.5	'
Cash and Securities Segregated under Federal and Other Regulations	88.1	22.3	'
Receivables from Clearing Organizations	3,104.60	3,679.40	'
Financial instruments, owned, at fair value	279.8	371.3	'
Assets, Fair Value Disclosure	3,477.30	4,084.20	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	265.6	360.2	'
Liabilities, Fair Value Disclosure	2,593.80	3,922.50	'
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	2,328.20	3,562.30	'
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Contingent Consideration [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] | Exchange firm common stock [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Financial instruments, owned, at fair value	4.4	3.4	'
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, at fair value	0	0	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	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, at fair value	7.7	14.8	'
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, at fair value	49.3	17.8	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	82.9	16.4	'
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, at fair value	0.1	0.3	'
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, at fair value	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]	'	'	'
Financial instruments, owned, at fair value	173.6	315.6	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	174	338.1	'
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, at fair value	4	7.5	'
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, at fair value	36.7	10	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	8.7	5.7	'
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, at fair value	4	1.9	'
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]	'	'	'
Receivables from Brokers-Dealers and Clearing Organizations	1.8	0.7	'
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]	'	'	'
Receivables from Clearing Organizations	841.4	335.1	'
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]	'	'	'
Receivables from 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]	'	'	'
Receivables from 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]	'	'	'
Receivables from Clearing Organizations	2,263.20	3,344.30	'
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]	'	'	'
Cash and Securities 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]	'	'	'
Cash and Securities Segregated under Federal and Other Regulations	13.1	22.3	'
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]	'	'	'
Cash and Securities 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]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	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]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	2.9	10.4	'
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	0	0	'
Cash and Securities Segregated under Federal and Other Regulations	19.5	50.5	'
Receivables from Clearing Organizations	600.1	1,325.30	'
Financial instruments, owned, at fair value	516.8	936	'
Assets, Fair Value Disclosure	1,136.60	2,316.80	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	575.3	1,001.10	'
Liabilities, Fair Value Disclosure	575.3	1,001.10	'
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 [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] | Exchange firm common stock [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Financial instruments, owned, at fair value	0	9	'
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, at fair value	56.1	135.2	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	85.5	220	'
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, at fair value	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, at fair value	19.8	5.6	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	16.6	5.9	'
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, at fair value	0	0.6	'
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, at fair value	0.3	0.3	'
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]	'	'	'
Financial instruments, owned, at fair value	440.6	785.3	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	473.2	775.2	'
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, at fair value	0	0	'
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, at fair value	0	0	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	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, at fair value	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]	'	'	'
Receivables from Brokers-Dealers and Clearing Organizations	0.2	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]	'	'	'
Receivables from 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]	'	'	'
Receivables from Clearing Organizations	594.8	1,318.30	'
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]	'	'	'
Receivables from Clearing Organizations	5.3	7	'
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]	'	'	'
Receivables from 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]	'	'	'
Cash and Securities 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]	'	'	'
Cash and Securities 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]	'	'	'
Cash and Securities Segregated under Federal and Other Regulations	19.5	50.5	'
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]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	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]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	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]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	0	0	'
Cash and Securities Segregated under Federal and Other Regulations	0	0	'
Receivables from Clearing Organizations	0	0	'
Financial instruments, owned, at fair value	4.2	4.5	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0	'
Liabilities, Fair Value Disclosure	9.6	14.8	'
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 [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Accounts payable and other accrued liabilities	9.6	14.8	'
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, 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, at fair value	0	0	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	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, at fair value	0	0	'
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, at fair value	0.7	0.9	'
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, at fair value	3.5	3.6	'
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, at fair value	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, at fair value	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, 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, at fair value	0	0	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	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, at fair value	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]	'	'	'
Receivables from Brokers-Dealers and 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]	'	'	'
Receivables from 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]	'	'	'
Receivables from 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]	'	'	'
Receivables from 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]	'	'	'
Receivables from 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]	'	'	'
Cash and Securities 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]	'	'	'
Cash and Securities 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]	'	'	'
Cash and Securities 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]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	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]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	0	0	'
Fair Value, Measurements, Recurring [Member] | Netting [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	0	0	'
Cash and Securities Segregated under Federal and Other Regulations	0	0	'
Receivables from Clearing Organizations	-2,333	-3,494.70	'
Financial instruments, owned, at fair value	-642.3	-1,140.10	'
Assets, Fair Value Disclosure	-2,990.40	-4,641.20	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	-661	-1,185.90	'
Liabilities, Fair Value Disclosure	-2,989.20	-4,748.20	'
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	-2,328.20	-3,562.30	'
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Contingent Consideration [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] | Exchange firm common stock [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Financial instruments, owned, at fair value	0	0	'
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, at fair value	-50	-93.1	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	-44.5	-117.2	'
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, at fair value	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, at fair value	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, at fair value	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]	'	'	'
Financial instruments, owned, at fair value	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, at fair value	-592.3	-1,047	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	-616.5	-1,068.70	'
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, 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, at fair value	0	0	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	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, at fair value	0	0	'
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Derivative [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Receivables from Brokers-Dealers and Clearing Organizations	-15.1	-6.4	'
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Money Market Funds [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Receivables from 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]	'	'	'
Receivables from 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]	'	'	'
Receivables from 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]	'	'	'
Receivables from Clearing Organizations	-2,333	-3,494.70	'
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Money Market Funds [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Cash and Securities 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]	'	'	'
Cash and Securities 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]	'	'	'
Cash and Securities 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]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	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]	'	'	'
Cash and Cash Equivalents, Fair Value Disclosure	0	0	'
Mutual funds and other [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	'	0	0.4
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	'	-0.4	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	'	0	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	'	0	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	'	0	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	'	0	'
Corporate Debt Securities [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	3.5	3.6	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, 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, Purchases	0	0	'
Common stock and American Depositary Receipts (ADRs) [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	0.7	0.9	1.1
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)	-0.2	-0.2	'
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, Purchases	0	0	'
Contingent Consideration [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	-13.4	-9.6	'
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	9.6	14.8	22.3
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)	2.6	2	3.1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	$5.60	$0.10	'

Assets_and_Liabilities_at_Fair5

Assets and Liabilities, at Fair Value - Suriwongse Bonds (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2013
Assets and Liabilities, at Fair Value [Abstract]	'	'
Suriwongse Debt Investment Balance	'	$3.50
Loss on Suriwongse Debt Investment	($1.70)	'

Assets_and_Liabilities_at_Fair6

Assets and Liabilities, at Fair Value - Contingent Consideration (Details) (Contingent Consideration [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Contingent Consideration [Member]	'	'	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease)	$2.60	$2	$3.10

Assets_and_Liabilities_at_Fair7

Assets and Liabilities, at Fair Value - Available for Sale Securities - Fin Inst (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale Debt Securities, Amortized Cost Basis	$573.70	$1,305.70
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	$573.80	$1,305.80

Assets_and_Liabilities_at_Fair8

Assets and Liabilities, at Fair Value - Available for Sale Securities - Dep and Rec (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale Debt Securities, Amortized Cost Basis	$573.70	$1,305.70
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	573.8	1,305.80
US Government Debt Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale Debt Securities, Amortized Cost Basis	568.5	1,298.90
Available-for-sale Securities, Gross Unrealized Gains	0	0
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities, Debt Securities	568.5	1,298.90
Collateralized Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale Debt Securities, Amortized Cost Basis	5.2	6.8
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	5.3	6.9
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	'
Available-for-sale Securities, Debt Securities	$573.80	$1,305.80

Assets_and_Liabilities_at_Fair9

Assets and Liabilities, at Fair Value - Available for Sale Securities (Maturities) (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	$568.50	$1,298.90
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value	5.3	6.9
Available-for-sale Securities, Debt Securities	573.8	1,305.80
US Government Debt Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	568.5	1,298.90
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value	0	0
Available-for-sale Securities, Debt Securities	568.5	1,298.90
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	5.3	6.9
Available-for-sale Securities, Debt Securities	$5.30	$6.90

Recovered_Sheet1

Assets and Liabilities, at Fair Value - Available for Sale Securities in OCI (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Assets and Liabilities, at Fair Value [Abstract]	'	'	'
Equity Investments in Exchange Stock - Cost	$3.70	'	$4.40
Equity Investments in Exchange Stock - Fair Value	4.4	'	12.4
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	0.5	'	-6.2
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	($0.30)	'	$2

Recovered_Sheet2

Assets and Liabilities, at Fair Value Assets and Liabilities, at Fair Value - Financial Instruments at Fair Value Disclosure (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Assets and Liabilities, at Fair Value [Abstract]	'	'
Long-term Debt, Fair Value	$46.40	'
Senior Notes	$45.50	$0

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 $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk [Abstract]	'	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	$179.90	$175.40
Derivatives Liabilties	$30.70	'

Financial_Instruments_with_Off3

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Derivatives Volume (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2013
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk [Abstract]	'	'
Notional Amount of Interest Rate Derivatives	$765	'
Derivative, Average Remaining Maturity	'6 months	'
Derivative, Number of Instruments Held	4,100,000	4,100,000

Financial_Instruments_with_Off4

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 $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	$2,879.40	$4,450.90
Derivative Liability, Fair Value, Gross Liability	2,975.40	4,675.60
Derivative Asset, Fair Value, Amount Offset Against Collateral	-2,940.40	-4,548.10
Derivative Liability, Fair Value, Amount Offset Against Collateral	-2,944.70	-4,631
Exchange-traded Commodity Contracts [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	2,036.60	3,325.60
Derivative Liability, Fair Value, Gross Liability	2,046.30	3,565.30
Over the Counter (OTC) Commodity Contracts [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	481.4	823.6
Derivative Liability, Fair Value, Gross Liability	484.9	841.4
Foreign Exchange Forward [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	89.3	63
Derivative Liability, Fair Value, Gross Liability	104.2	47.7
Over the Counter (OTC) Foreign Exchange Contracts [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	132.3	215.4
Derivative Liability, Fair Value, Gross Liability	162.3	196.6
Exchange-traded interest rate contracts [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	4.3	0.9
Derivative Liability, Fair Value, Gross Liability	36	2.6
Interest Rate Contract [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	0	1.6
Derivative Liability, Fair Value, Gross Liability	0	0
Equity Contract [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Gross Asset	135.5	20.8
Derivative Liability, Fair Value, Gross Liability	141.7	22
Deposits and receivables from exchange clearing organizations [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative, Fair Value, Net	-69.8	-150.4
Deposits and receivables from broker-dealers, clearing organizations and counterparties [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative, Fair Value, Net	-13.1	-0.7
Financial instruments owned [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative, Fair Value, Net	21.9	53.9
Financial instrument sold, not yet purchased [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative, Fair Value, Net	$30.70	$44.60

Financial_Instruments_with_Off5

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Realized Gains/Losses on Derivative Contracts (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Commodity Contract [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$84.60	$62.30	$32.80
Foreign Exchange Forward [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Derivative Instruments, Gain (Loss) Recognized in Income, Net	11.6	10.4	15
Interest Rate Contract [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Derivative Instruments, Gain (Loss) Recognized in Income, Net	0.1	1.4	3.5
Derivative [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$96.30	$74.10	$51.30

Financial_Instruments_with_Off6

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk Interest Rate Cash Flow Hedges (Details) (USD $)	Sep. 30, 2012
In Millions, unless otherwise specified
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Notional Amount of Interest Rate Derivatives	$765

Receivables_from_customers_net2

Receivables from customers, net and notes receivable, net - Allowance for Customer Receivables (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Receivables from customers and notes receivable, net [Abstract]	'	'	'
Allowance for Doubtful Accounts Receivable	$1.10	$0.90	'
Closed Derivative Contracts - Deficit Balance	$0	$0	$2.50

Receivables_from_customers_net3

Receivables from customers, net and notes receivable, net - Allowance for Notes Receivable (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
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 - Bad Debt Expense and Recoveries (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'
Provision for Doubtful Accounts	$0.20	$0.50	$6.80
Allowance for Doubtful Accounts Receivable, Charge-offs	0	-11.2	-113.3
Allowance for Doubtful Accounts Receivable, Recoveries	0	-0.1	-3.7
Commodity and Risk Management [Member]	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'
Provision for Doubtful Accounts	0.7	0.7	4.5
Allowance for Doubtful Accounts Receivable, Charge-offs	0.6	0.3	1.4
Allowance for Doubtful Accounts Receivable, Recoveries	0.1	0.1	3.7
Consigned gold charge-off	'	8.5	'
CR&M customer deficit charge-off	'	'	3.7
CES Segment [Member]	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'
CES customer deficits charge-off	'	$2.70	'

Receivables_from_customers_net5

Receivables from customers, net and notes receivable, net - Allowance for Bad Debts Rollforward (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Allowance for Doubtful Accounts Receivable [Roll Forward]	'	'	'
Allowance for Doubtful Accounts - Customer and Notes Receivable	$1	$11.90	$119.20
Provision for bad debts	0.2	0.4	7.2
Closed Derivative Contracts - Deficit Balance	0	0	2.5
Allowance for Doubtful Accounts Receivable, Charge-offs	0	-11.2	-113.3
Allowance for Doubtful Accounts Receivable, Recoveries	0	-0.1	-3.7
Allowance for Doubtful Accounts - Customer and Notes Receivable	$1.20	$1	$11.90

Receivables_from_customers_net6

Receivables from customers, net and notes receivable, net - Notes Receivable (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable, Charge-offs	$0	($11.20)	($113.30)
Allowance for Doubtful Accounts Receivable, Recoveries	0	-0.1	-3.7
FCStone LLC [Member]	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'
Remaining Acquired Notes Receivable	0.7	'	'
Notes receivable charge-off during the year	'	'	$111.50

Receivables_from_customers_net7

Receivables from customers, net and notes receivable, net Exim Bank Notes Receivable (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Insured short-term notes receivable	$21.10	$10.20
Obligations for participation rights	$18.70	$0.80
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 - Inventory Serving as Collateral (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Physical Commodities Inventory [Abstract]	'	'
Inventory Adjustments	$0.90	$0.40

Physical_Commodities_Inventory3

Physical Commodities Inventory - Physical Commodities Inventory by CIP and Finished (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Physical Commodities Inventory [Abstract]	'	'
Commodities in process	$0	$13.60
Finished commodities	59	118
Physical commodities inventory	$59	$131.60

Property_and_Equipment_net_Pro

Property and Equipment, net Property and Equipment, net (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Property, Plant and Equipment [Line Items]	'	'	'
Depreciation	$5.80	$4.70	$2.40
Furniture and Fixtures, Gross	6	6.3	'
Capitalized Computer Software, Gross	6	3.9	'
Machinery and Equipment, Gross	10.2	9.3	'
Leasehold Improvements, Gross	9.6	9	'
Property, Plant and Equipment, Gross	31.8	28.5	'
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	14.3	9.6	'
Property, Plant and Equipment, Net	$17.50	$18.90	'
Minimum [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, Plant and Equipment, Estimated Useful Lives	'3 years	'	'
Maximum [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, Plant and Equipment, Estimated Useful Lives	'10 years	'	'

Goodwill_Goodwill_by_Segment_D

Goodwill - Goodwill by Segment (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Goodwill [Line Items]	'	'
Goodwill	$47.50	$44.70
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	$5.30

Goodwill_Additions_to_Goodwill

Goodwill Additions to Goodwill (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Goodwill [Abstract]	'	'
Goodwill, Acquired During Period	$2.80	$1.10

Intangible_Assets_Gross_and_Ne

Intangible Assets - Gross and Net Intangible Assets by Major Class (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Finite-Lived Trade Names, Gross	'	$0.10
Finite-Lived Intangible Assets, Gross	19	16.2
Finite-Lived Intangible Assets, Accumulated Amortization	-8.5	-6.3
Finite-Lived Intangible Assets, Net	10.5	9.9
Goodwill	47.5	44.7
Gross Finite and Indefinite-Lived Intangible Assets	20.1	17.4
Finite and Indefinited-Lived Accumulated Amortization and Impairment Charges	-8.5	-6.3
Intangible Assets, Net (Excluding Goodwill)	11.6	11.1
Noncompete Agreements [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Finite-Lived Noncompete Agreements, Gross	3.7	3.7
Finite-Lived Intangible Assets, Accumulated Amortization	-3.7	-3
Finite-Lived Intangible Assets, Net	0	0.7
Trade Names [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Finite-Lived Trade Names, Gross	0.7	0.7
Finite-Lived Intangible Assets, Accumulated Amortization	-0.7	-0.5
Finite-Lived Intangible Assets, Net	0	0.2
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	-1.5	-1
Finite-Lived Intangible Assets, Net	0.7	1.2
Customer Relationships [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Finite-Lived Customer Lists, Gross	12.4	9.6
Finite-Lived Intangible Assets, Accumulated Amortization	-2.6	-1.8
Finite-Lived Intangible Assets, Net	$9.80	$7.80

Intangible_Assets_IndefiniteLi

Intangible Assets - Indefinite-Lived Intangible Assets (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Indefinite-lived Intangible Assets [Line Items]	'	'
Gross Finite and Indefinite-Lived Intangible Assets	$20.10	$17.40
Finite and Indefinited-Lived Accumulated Amortization and Impairment Charges	-8.5	-6.3
Intangible Assets, Net (Excluding Goodwill)	11.6	11.1
Trade Names [Member]	'	'
Indefinite-lived Intangible Assets [Line Items]	'	'
Indefinite-Lived Trade Names	1.1	1.2
Indefinite-lived Intangible Assets, Impairment Losses	$0	$0

Intangible_Assets_FiniteLived_

Intangible Assets - Finite-Lived Intangible Assets Future Amortization Expense (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Intangible Assets [Abstract]	'	'	'
Amortization of Intangible Assets	$2.20	$2.50	$2.30
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]	'	'	'
Fiscal 2013	1.4	'	'
Fiscal 2014	1	'	'
Fiscal 2015	0.7	'	'
Fiscal 2016	0.7	'	'
Fiscal 2017	0.7	'	'
Fiscal 2018 and thereafter	6	'	'
Finite-Lived Intangible Assets, Net	$10.50	$9.90	'

Intangible_Assets_Intangible_I

Intangible Assets Intangible Impairments (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Intangible Assets [Abstract]	'	'
Impairment of Intangible Assets (Excluding Goodwill)	($0.10)	($0.80)
Finite-Lived Intangible Assets, Gross	'	$0.10

Credit_Facilities_Number_of_Cr

Credit Facilities - Number of Credit Facilities (Details) (USD $)	12 Months Ended			12 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
		Main line of credit facilities [Member]	Main line of credit facilities [Member]	HCO Syndicated line of credit facility [Member]	INTL COM line of credit facility [Member]	FCS Margin line of credit facility [Member]	Eurodollar Rate [Member]	Base Rate [Member]	Base Rate [Member]
				Rate		Rate	HCO Syndicated line of credit facility [Member]	HCO Syndicated line of credit facility [Member]	FCS Margin line of credit facility [Member]
Line of Credit Facility [Line Items]	'	'	'	'	'	'	'	'	'
Line of Credit Facility, Maximum Borrowing Capacity	'	$290	$150	$140	$0	$75	'	'	'
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	'	'	'	0.63%	'	0.50%	'	'	'
Debt Instrument, Basis Spread on Variable Rate	'	'	'	'	'	'	3.00%	2.00%	2.00%
Line of Credit Facility, Interest Rate at Period End	'	'	'	3.72%	'	5.25%	'	'	'
Debt Issuance Cost	$1.70	'	'	$1.50	'	'	'	'	'
Number of credit facilities	3	'	'	'	'	'	'	'	'

Credit_Facilities_Details

Credit Facilities (Details) (USD $)

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

In Millions, unless otherwise specified

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Nov. 15, 2013

Main line of credit facilities [Member]

Main line of credit facilities [Member]

INTL COM line of credit facility [Member]

INTL COM line of credit facility [Member]

HCO Syndicated line of credit facility [Member]

HCO Syndicated line of credit facility [Member]

FCS Margin line of credit facility [Member]

FCS Margin line of credit facility [Member]

FMS Sub-note commodity line of credit facility [Member]

FMS Sub-note commodity line of credit facility [Member]

INTL FCStone, Ltd [Member]

Rate

Rate

Rate

Line of Credit Facility [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of Credit Facility, Interest Rate at Period End

'

'

'

'

'

'

3.72%

'

5.25%

'

3.75%

'

'

Line of Credit Facility, Maximum Borrowing Capacity

'

'

$290

$150

$0

'

$140

'

$75

'

$75

'

$25

Line of Credit Facility, Unused Capacity, Commitment Fee Percentage

'

'

'

'

'

'

0.63%

'

0.50%

'

0.50%

'

'

Line of Credit Facility, Amount Outstanding

61

218.2

'

'

0

107

55

48

0

20

6

43.2

'

Senior Notes

45.5

0

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Interest Rate, Stated Percentage

8.50%

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Call Feature, Redemption Price Percentage of Principal

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

Debt Issuance Cost

1.7

'

'

'

'

'

1.5

'

'

'

'

'

'

Debt and Capital Lease Obligations

$106.50

$218.20

'

'

'

'

'

'

'

'

'

'

'

Commitments_and_Contingencies_2

Commitments and Contingencies - Contingencies and Litigation (Details) (USD $)	12 Months Ended
	Sep. 30, 2013
Sentinel Appeal Cash Deposit	$8,000,000
Loss Contingency, Settlement Agreement, Consideration	265,000
Loss Contingency, Loss in Period	1,500,000
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
Minimum [Member]	'
Excess segregated funds returned	4,000,000
Maximum [Member]	'
Excess segregated funds returned	$6,000,000

Commitments_and_Contingencies_3

Commitments and Contingencies - Contigent Consideration for Acquisitions (Details) (USD $)

12 Months Ended

12 Months Ended

12 Months Ended

In Millions, unless otherwise specified

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2012

Jul. 08, 2013

Sep. 30, 2013

Sep. 30, 2012

Jun. 30, 2013

Sep. 30, 2013

Oct. 31, 2010

Sep. 30, 2013

Jun. 30, 2013

Nov. 30, 2011

Sep. 30, 2013

Oct. 31, 2011

Oct. 31, 2010

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Tradewire Acquisition [Member] [Member]

Hencorp Acquisition [Member]

Hencorp Acquisition [Member]

Hanley Group Acquisition [Member]

RMI-RMC Acquistion [Member]

RMI-RMC Acquistion [Member]

RMI-RMC Acquistion [Member]

Tradewire Acquisition [Member] [Member]

Tradewire Acquisition [Member] [Member]

Tradewire Acquisition [Member] [Member]

Coffee Network Acquisition [Member]

Coffee Network Acquisition [Member]

Hencorp Acquisition [Member]

Hencorp Acquisition [Member]

Hencorp Acquisition [Member]

Hanley Group Acquisition [Member]

Hanley Group Acquisition [Member]

Contingent Consideration [Member]

Contingent Consideration [Member]

Contingent Consideration [Member]

Business Acquisition, Contingent Consideration [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Accounts payable and other accrued liabilities - contingent consideration, fair value

$9.60

$14.80

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2.6

2

3.1

Business Combination, Consideration Transferred

'

'

'

'

'

'

'

'

'

'

'

'

5.6

'

0.3

'

'

'

'

'

'

'

'

Business Acquisition, Contingent Consideration, Potential Cash Payment

'

'

'

'

'

'

-10

'

'

'

'

'

'

'

'

'

0.7

'

'

'

'

'

'

Business Acquisition, Contingent Consideration, Potential Cash Payment, Year One

'

'

'

'

'

'

'

'

'

'

'

0.9

'

'

'

'

0.7

'

'

'

'

'

'

Business Acquisition, Contingent Consideration, Potential Cash Payment, Year Two

'

'

'

'

'

'

'

'

'

'

'

2

'

'

'

'

2.8

'

'

'

'

'

'

Business Acquisition, Contingent Consideration, Potential Cash Payment Year Three

'

'

'

'

'

'

'

'

'

'

'

5.5

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability

8.2

2.1

5.4

0.7

1

0.1

'

0.2

0

'

'

'

'

'

'

'

'

'

0.7

2

'

'

'

Business Combination, Consideration, Including Contingent Consideration

'

'

'

'

'

'

'

'

'

'

6.3

'

'

'

'

'

7.5

'

'

'

'

'

'

Business Acquisition, Cost of Acquired Entity, Purchase Price

'

'

'

'

'

'

'

'

'

'

'

'

'

0.1

'

7.5

'

'

'

'

'

'

'

Business Acquisition, Contingent Consideration, at Fair Value

'

'

'

'

3.2

'

'

'

'

-3.1

'

'

'

'

0.1

'

'

2.3

'

'

'

'

'

Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed

'

$0.40

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Commitments_and_Contingencies_4

Commitments and Contingencies Operating Leases (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Operating Leases [Abstract]	'	'	'
Operating Leases, Rent Expense	$9.20	$8.90	$7.20
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]	'	'	'
Operating Leases, Future Minimum Payments Due, Next Twelve Months	6.7	'	'
Operating Leases, Future Minimum Payments, Due in Two Years	5.8	'	'
Operating Leases, Future Minimum Payments, Due in Three Years	4.5	'	'
Operating Leases, Future Minimum Payments, Due in Four Years	4	'	'
Operating Leases, Future Minimum Payments, Due in Five Years	3.7	'	'
Operating Leases, Future Minimum Payments, Due Thereafter	10.2	'	'
Operating Leases, Future Minimum Payments Due	$34.90	'	'

Commitments_and_Contingencies_5

Commitments and Contingencies Purchase Obligations (Details) (USD $)	Sep. 30, 2013
In Millions, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]	'
Purchase Obligation, Due in Next Twelve Months	$298.70
Purchase Obligation, Due in Second and Third Year	6.8
Purchase Obligation, Due in Fourth and Fifth Year	3.4
Purchase Obligation, Due after Fifth Year	1.6
Other Commitment, Due in Next Twelve Months	$216.60

Regulatory_Requirements_and_Su2

Regulatory Requirements and Subsidiary Dividend Restrictions - Minimum net capital (Details)	Sep. 30, 2013
Capital and Other Regulatory Requirements [Abstract]	'
Ratio of Indebtedness to Net Capital	15
Ratio of Indebtedness to Net Capital - Equity Withdrawal Limitation	10

Regulatory_Requirements_and_Su3

Regulatory Requirements and Subsidiary Dividend Restrictions - Regulatory Capital Requirements (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Cash and Securities Segregated under Commodity Exchange Act Regulation	$1,693.50	$1,665.50
Cash and Securities Segregated under Commodity Exchange Act Regulation, Amount Required to be Segregated	-1,669.60	-1,620.50
Secured funds	82.5	89.3
Secured Funds Required Under Commodity Exchange Act	-59.8	-77.6
FCStone LLC [Member]	'	'
Net Capital under Commodity Exchange Act Computation	106.3	'
Required Net Capital under Commodity Exchange Act	66.3	'
INTL FCStone Europe [Member]	'	'
Net Capital under Commodity Exchange Act Computation	60.8	'
Required Net Capital under Commodity Exchange Act	23.4	'
Cash and Securities Segregated under Commodity Exchange Act Regulation	61.2	'
Cash and Securities Segregated under Commodity Exchange Act Regulation, Amount Required to be Segregated	61.1	'
INTL Global Currencies [Member]	'	'
Net Capital under Commodity Exchange Act Computation	11.4	'
Required Net Capital under Commodity Exchange Act	1.2	'
INTL Trading [Member]	'	'
Net Capital	5	'
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	1.8	'
Required Net Capital under Commodity Exchange Act	0.9	'
Net Capital	11.6	'
Capital Required for Capital Adequacy	4.1	'
FCStone Europe [Member]	'	'
Net Capital under Commodity Exchange Act Computation	2	'
Required Net Capital under Commodity Exchange Act	0.6	'
INTL FCStone DTVM Ltda [Member]	'	'
Net Capital	0.7	'
Capital Required for Capital Adequacy	0.7	'
INTL Capital S.A – Rosario Futures Exchanges [Member] [Domain]	'	'
Net Capital	6.3	'
Capital Required for Capital Adequacy	0.1	'
INTL Capital S.A. – General Inspector of Justice [Member] [Domain]	'	'
Net Capital under Commodity Exchange Act Computation	8.5	'
Required Net Capital under Commodity Exchange Act	6.4	'
INTL Capital S.A. – Superintendence of Securities Markets of Buenos Aires [Member] [Domain]	'	'
Net Capital under Commodity Exchange Act Computation	4	'
Required Net Capital under Commodity Exchange Act	$0.30	'

Regulatory_Requirements_and_Su4

Regulatory Requirements and Subsidiary Dividend Restrictions Regulatory Requirements and Subsidiary Dividend Restrictions - Customer Secured Funds (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Cash and Securities Segregated under Commodity Exchange Act [Abstract]	'	'
Cash Segregated under Commodity Exchange Act Regulation	$247.60	$225.60
Securities Segregated under Commodity Exchange Act Regulation	0	0
Securities Held for Customers in Lieu of Cash, At Banks, Segregated under Commodity Exchange Act Regulation	19.5	47.2
Deposits with and Receivables From Clearing Organizations, Segregated under Commodity Exchange Act Regulation	1,413.30	1,370.40
Securities Held for Customers in Lieu of Cash, Segregated under Commodity Exchange Act Regulation	13.1	22.3
Cash and Securities Segregated under Commodity Exchange Act Regulation	1,693.50	1,665.50
Cash and Securities Segregated under Commodity Exchange Act Regulation, Amount Required to be Segregated	1,669.60	1,620.50
Cash and Securities Segregated under Commodity Exchange Act Regulation, Excess Funds in Segregation	23.9	45
Cash and Securities Segregated under Other Regulations [Abstract]	'	'
Cash Segregated under Other Regulations	34.2	25.2
Securities Segregated under Other Regulations	0	3.3
Equities with Futures Commission Merchants Segregated under Other Regulations	27	9.9
Amounts Held by Clearing Organizations Segregated under Other Regulations	0	20.8
Amounts Held by Members of Foreign Boards of Trade Segregated under Other Regulations	21.3	30.1
Secured funds	82.5	89.3
Secured Funds Required Under Commodity Exchange Act	59.8	77.6
Cash and Securities Segregated under Other Regulations	$22.70	$11.70

Commodity_and_Other_Repurchase1

Commodity and Other Repurchase Agreements Commodity and Other Repurchase Agreements (Details) (USD $)	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified			Broker-dealers, Clearing Organizations and Counterparties [Member]	Broker-dealers, Clearing Organizations and Counterparties [Member]	Lenders Under Loans [Member]	Lenders Under Loans [Member]
Assets Sold under Agreements to Repurchase [Line Items]	'	'	'	'	'	'
Sales Repurchase Agreements	$9.20	$92.50	'	'	'	'
Obligations outstanding related to commodities sold under repurchase agreements	'	'	$0	$37	$6	$43.20

ShareBased_Compensation_Stockb

Share-Based Compensation - Stock-based Compensation Expense (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'
Allocated Share-based Compensation Expense	$9.30	$5.90	$2.30

ShareBased_Compensation_Stock_

Share-Based Compensation - Stock Option Plan (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options	$10	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	'	1,000,000	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'5 years 8 months 16 days	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$2	$3	$1.60
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,000,000	921,412	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$4.21	$13.57	$11.66

ShareBased_Compensation_Stock_1

Share-Based Compensation - Stock Option Plan Fair Value Weighted-Average Assumptions (Details)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	35.00%	57.00%	77.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	0.00%	0.00%	0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	0.37%	1.53%	0.72%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	'2 years 10 months 17 days	'7 years 10 months 10 days	'2 years 11 months 9 days

ShareBased_Compensation_Stock_2

Share-Based Compensation - Stock Based Compensation Table (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	921,412	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,890,634	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized	1,000,000	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	-100,000	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Period Increase (Decrease)	100,000	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	-177,246	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Other Increases (Decreases) in Period	-32,738	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period, Net	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	-667	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,000,000	921,412	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,779,983	1,890,634	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	680,820	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$24.76	$23.36	'
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$17.53	'	'
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$8.40	'	'
Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price	$10.35	'	'
Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price	$23.49	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$27.47	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Grant Date Fair Value	$11.44	$11.11	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$4.21	$13.57	$11.66
Share-based Compensation Arrangement by Share-based Payment Award, Options, Excrecises in Period, Weighted Average Grant Date Fair Value	$5.26	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeited in Period, Weighted Average Grant Date Fair Value	$3.88	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expired in Period, Weighted Average Grant Date Fair Value	$11.58	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Excercisable, Weighted Average Grant Date Fair Value	$11.04	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	'4 years 10 months 13 days	'5 years 5 months 12 days	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	'1 year 10 months 28 days	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$4.80	$6	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	3.1	'	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options	10	'	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'5 years 8 months 16 days	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$2	$3	$1.60
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	'	1,000,000	'

ShareBased_Compensation_Restri

Share-Based Compensation - Restricted Stock Plan (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Jul. 02, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period	'	1,500,000	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$4.90	'	$2.60
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition - Restricted Stock	'1 year 8 months 27 days	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	1,154,862	1,420,114	'

ShareBased_Compensation_Option

Share-Based Compensation Options by Exercise Price (Details) (USD $)	12 Months Ended
	Sep. 30, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number of Outstanding Options	1,779,983
Weighted Average Exercise Price	$24.76
Weighted Average Remaining Term (in years)	'4 years 10 months 13 days
$0 - $5,00 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number of Outstanding Options	0
Exercise Price Range, Lower Range Limit	$0
Exercise Price Range, Upper Range Limit	$5
$5.00 - $10.00 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number of Outstanding Options	301,875
Weighted Average Exercise Price	$7.02
Weighted Average Remaining Term (in years)	'1 year 2 months 5 days
Exercise Price Range, Lower Range Limit	$5
Exercise Price Range, Upper Range Limit	$10
$10.00 - $15.00 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number of Outstanding Options	0
Exercise Price Range, Lower Range Limit	$10
Exercise Price Range, Upper Range Limit	$15
$15.00 - $20.00 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number of Outstanding Options	322,179
Weighted Average Exercise Price	$18.01
Weighted Average Remaining Term (in years)	'2 years 4 months 24 days
Exercise Price Range, Lower Range Limit	$15
Exercise Price Range, Upper Range Limit	$20
$20.00 - $25.00 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number of Outstanding Options	126,204
Weighted Average Exercise Price	$23.52
Weighted Average Remaining Term (in years)	'3 years 1 month 6 days
Exercise Price Range, Lower Range Limit	$20
Exercise Price Range, Upper Range Limit	$25
$25.00 - $30.00 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number of Outstanding Options	800,000
Weighted Average Exercise Price	$25.91
Weighted Average Remaining Term (in years)	'8 years 2 months 19 days
Exercise Price Range, Lower Range Limit	$25
Exercise Price Range, Upper Range Limit	$30
$30.00 - $35.00 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number of Outstanding Options	0
Exercise Price Range, Lower Range Limit	$30
Exercise Price Range, Upper Range Limit	$35
$35.00 - $40.00 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number of Outstanding Options	0
Exercise Price Range, Lower Range Limit	$35
Exercise Price Range, Upper Range Limit	$40
$40.00 - $45.00 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number of Outstanding Options	0
Exercise Price Range, Lower Range Limit	$40
Exercise Price Range, Upper Range Limit	$45
$45.00 - $50.00 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number of Outstanding Options	0
Exercise Price Range, Lower Range Limit	$45
Exercise Price Range, Upper Range Limit	$50
$50.00 - $55.00 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number of Outstanding Options	229,725
Weighted Average Exercise Price	$54.23
Weighted Average Remaining Term (in years)	'2 years 5 months 12 days
Exercise Price Range, Lower Range Limit	$50
Exercise Price Range, Upper Range Limit	$55

ShareBased_Compensation_Restri1

Share-Based Compensation - Restricted Stock Plan Table (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Jul. 02, 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	1,154,862	1,420,114	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	512,124	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period	'	1,500,000	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Period Increase (Decrease)	-268,885	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	268,885	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	-406,901	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	-10,470	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Forfeitures	3,633	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	1,154,862	1,420,114	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	363,638	512,124	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$20.53	$22.09	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$17.92	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$20.72	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$22.62	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms	'1 year 8 months 27 days	'1 year 9 months 22 days	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Intrinsic Value	$7,400,000	$9,800,000	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$4.90	'	$2.60
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition - Restricted Stock	'1 year 8 months 27 days	'	'

Retirement_Plans_Retirement_Pl1

Retirement Plans Retirement Plans (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
	Rate	Rate
Defined Benefit Plan, Fair Value of Plan Assets	$28.90	$26.50	$24.20	$24.20
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax	-4.6	2.9	'	'
Defined Contribution Plan, Employer Discretionary Contribution Amount	4	3.7	2.8	'
Defined Benefit Plan, Actual Plan Asset Allocations	100.00%	100.00%	'	'
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, before Tax	-0.8	-0.4	'	'
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	3.80%	4.80%	5.30%	'
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.60%	3.80%	'	'
Defined Benefit Plan, Accumulated Benefit Obligation	37.5	42.8	'	'
Defined Benefit Plan, Benefit Obligation	37.5	42.8	39	37.6
Defined Benefit Plan, Interest Cost	1.5	1.8	1.9	'
Defined Benefit Plan, Expected Return on Plan Assets	1.8	1.7	1.7	'
Defined Benefit Plan, Actuarial Gain (Loss)	-2.6	5.8	2.6	'
Defined Benefit Plan, Expected Future Benefit Payments, Total	24.4	'	'	'
Defined Benefit Plan, Actual Return on Plan Assets	3.7	4.6	-0.4	'
Defined Benefit Plan, Contributions by Employer	2.9	1.5	3.5	'
Defined Benefit Plan, Benefits Paid	-4.2	-3.8	-3.1	'
Defined Benefit Plan, Funded Status of Plan	-8.6	-16.3	-14.8	'
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax	2.9	6.2	'	'
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	0.2	'	'	'
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	2.5	'	'	'
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Projected Benefit Obligation	37.5	42.8	'	'
Defined Benefit Plan, Expected Return on Plan Assets	-7.00%	-7.00%	'	'
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets	7.00%	7.30%	7.30%	'
Defined Benefit Plan, Amortization of Gains (Losses)	0.8	0.4	0	'
Defined Benefit Plan, Net Periodic Benefit Cost	0.5	0.5	0.2	'
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	3.6	'	'	'
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	3.3	'	'	'
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	3.2	'	'	'
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	2.9	'	'	'
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	1.9	'	'	'
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	9.5	'	'	'
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Gain (Loss), before Tax	-5.4	2.5	'	'
Defined Benefit Plan, Amounts Recognized in Net Periodic Benefit Cost and Other Comprehensive Income (Loss), Net Gain (Loss), before Tax	-4.9	3	'	'
Debt Securities [Member]	'	'	'	'
Defined Benefit Plan, Actual Plan Asset Allocations	32.00%	34.00%	'	'
Defined Benefit Plan, Target Allocation Percentage	'0.3	'	'	'
Equity Securities [Member]	'	'	'	'
Defined Benefit Plan, Actual Plan Asset Allocations	68.00%	66.00%	'	'
Defined Benefit Plan, Target Allocation Percentage	'0.7	'	'	'
Other Assets [Member]	'	'	'	'
Defined Benefit Plan, Amounts Recognized in Balance Sheet	0.5	0.1	'	'
Other Liabilities [Member]	'	'	'	'
Defined Benefit Plan, Amounts Recognized in Balance Sheet	-9.1	-16.4	'	'
Fair Value, Inputs, Level 1 [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0	0	'	'
Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0	0	'	'
Fair Value, Inputs, Level 1 [Member] | US Treasury and Government [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0	0	'	'
Fair Value, Inputs, Level 1 [Member] | Debt Securities [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0	0	'	'
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0	0	'	'
Fair Value, Inputs, Level 1 [Member] | Real Estate [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0	0	'	'
Fair Value, Inputs, Level 2 [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	28.9	26.5	'	'
Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0.5	0.4	'	'
Fair Value, Inputs, Level 2 [Member] | US Treasury and Government [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0.6	0.8	'	'
Fair Value, Inputs, Level 2 [Member] | Debt Securities [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	8.1	7.7	'	'
Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	18.7	16.6	'	'
Fair Value, Inputs, Level 2 [Member] | Real Estate [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	1	1	'	'
Fair Value, Inputs, Level 3 [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0	0	'	'
Fair Value, Inputs, Level 3 [Member] | Cash and Cash Equivalents [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0	0	'	'
Fair Value, Inputs, Level 3 [Member] | US Treasury and Government [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0	0	'	'
Fair Value, Inputs, Level 3 [Member] | Debt Securities [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0	0	'	'
Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0	0	'	'
Fair Value, Inputs, Level 3 [Member] | Real Estate [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0	0	'	'
Estimate of Fair Value, Fair Value Disclosure [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	28.9	26.5	'	'
Estimate of Fair Value, Fair Value Disclosure [Member] | Cash and Cash Equivalents [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0.5	0.4	'	'
Estimate of Fair Value, Fair Value Disclosure [Member] | US Treasury and Government [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	0.6	0.8	'	'
Estimate of Fair Value, Fair Value Disclosure [Member] | Debt Securities [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	8.1	7.7	'	'
Estimate of Fair Value, Fair Value Disclosure [Member] | Equity Securities [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	18.7	16.6	'	'
Estimate of Fair Value, Fair Value Disclosure [Member] | Real Estate [Member]	'	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	$1	$1	'	'
UK Plan [Member]	'	'	'	'
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage	100.00%	'	'	'
UK Plan [Member] | Maximum [Member]	'	'	'	'
Defined Contribution Plan, Employer Matching Contribution, Percent	10.00%	'	'	'
401k Plan [Member]	'	'	'	'
Defined Contribution Plan, Employer Matching Contribution, Percent	62.50%	'	'	'
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage	8.00%	'	'	'
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage, Two to Three Years	20.00%	'	'	'
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage, Three to Four Years	40.00%	'	'	'
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage, Four to Five Years	60.00%	'	'	'
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage, All Years	100.00%	'	'	'
401k Plan [Member] | Maximum [Member]	'	'	'	'
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Percent	80.00%	'	'	'
401k Plan [Member] | Minimum [Member]	'	'	'	'
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Percent	1.00%	'	'	'

Other_Expenses_Other_Expenses_

Other Expenses - Other Expenses Breakout (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Component of Operating Other Cost and Expense [Line Items]	'	'	'
Other Cost and Expense, Operating	$23.20	$21.60	$21.40
Clearance Fees	1.6	1.7	1.8
Contingent Consideration [Member]	'	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'	'
Other Cost and Expense, Operating	3	2.9	4.7
Insurance Expense [Member]	'	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'	'
Other Cost and Expense, Operating	1.8	1.7	1.5
Advertising, Meetings and Conferences [Member]	'	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'	'
Other Cost and Expense, Operating	2.3	2.5	1.8
Non-trading hardware and software maintenance and software licensing [Member]	'	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'	'
Other Cost and Expense, Operating	2.7	2.2	2.8
Office supplies and printing [Member]	'	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'	'
Other Cost and Expense, Operating	1.2	1.3	1.1
Taxes Other than Income and Excise Taxes [Member]	'	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'	'
Other Cost and Expense, Operating	3.8	4	2.8
Other Operating Expense [Member]	'	'	'
Component of Operating Other Cost and Expense [Line Items]	'	'	'
Other Cost and Expense, Operating	$6.80	$5.30	$4.90

Income_Taxes_Details

Income Taxes (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Taxes [Abstract]	'	'	'
Deferred Tax Assets, Net of Valuation Allowance, Operating Loss Carryforwards, State and Local	$4.50	'	'
Valuation Allowance, Deferred Tax Asset, Change in Amount	1.8	'	'
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	3.1	'
Undistributed Earnings of Foreign Subsidiaries	123.1	93.8	'
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	0.1	'	'
Income Tax Expense (Benefit), Continuing Operations	3.3	3.1	20.9
Discontinued Operation, Tax Effect of Discontinued Operation	0	0	0.1
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	-1.6	2.2	-0.3
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized (Gain) Loss Arising During Period, Tax	1.8	-1	-1.7
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	0	0	0.6
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	0	-0.2	0
Other Comprehensive Income (Loss), Tax	3.5	4.1	19.6
Operating Loss Carryforwards	11.8	2.8	'
Deferred Tax Assets, Valuation Allowance	-2.3	-4.1	'
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	0	0.2	'
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	($0.20)	$0.30	$0.20

Income_Taxes_Current_and_Defer

Income Taxes Current and Deferred Taxes (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Abstract]	'	'	'
Current Federal Tax Expense (Benefit)	($1.20)	($6.90)	$7.60
Current State and Local Tax Expense (Benefit)	-1.3	0.4	1.6
Current Foreign Tax Expense (Benefit)	13.5	10.1	9.9
Current Income Tax Expense (Benefit)	11	3.6	19.1
Deferred Income Tax Expense (Benefit)	-7.7	-0.5	1.8
Income Tax Expense (Benefit), Continuing Operations	$3.30	$3.10	$20.90

Income_Taxes_US_and_Internatio

Income Taxes US and International Taxes (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Abstract]	'	'	'
Income (Loss) from Continuing Operations before Income Taxes, Domestic	($21.70)	($17.20)	$23.20
Income (Loss) from Continuing Operations before Income Taxes, Foreign	44.3	33	32.2
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	$22.60	$15.80	$55.40

Income_Taxes_Effective_Rate_Re

Income Taxes Effective Rate Reconciliation (Details)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
	Rate	Rate	Rate
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate	35.00%	35.00%	35.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes	0.80%	-2.00%	0.80%
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential	-20.10%	-20.40%	-3.10%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate	-2.40%	0.00%	1.20%
Effective Income Tax Rate Reconciliation, Tax Contingencies	-0.30%	-1.50%	1.50%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Meals and Entertainment	1.30%	2.70%	0.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other	4.30%	6.00%	0.00%
Effective Income Tax Rate Reconciliation, Deductions, Other	3.90%	-4.20%	0.60%
Effective Income Tax Rate Reconciliation, Other Adjustments	2.40%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Tax Settlements	-1.70%	0.00%	0.00%
Effective Income Tax Rate, Continuing Operations	15.40%	17.60%	37.70%
Foreign Tax Authority [Member]	'	'	'
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance	-0.20%	2.20%	0.70%
State and Local Jurisdiction [Member]	'	'	'
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance	-7.60%	-0.20%	1.00%

Income_Taxes_Deferred_Tax_Asse

Income Taxes Deferred Tax Assets and Liabilites (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified
Income Tax Disclosure [Abstract]	'	'
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	$2.70	$2.50
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Pensions	3.4	6.1
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation	2.3	3.2
Deferred Tax Assets, Operating Loss Carryforwards, Foreign	1.9	2
Deferred Tax Assets, Operating Loss Carryforwards, State and Local	4.9	4.9
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	7.3	0
Deferred Tax Liabilities, Intangible Assets	6.9	6.1
Deferred Tax Assets, Equity Method Investments	0.7	1.1
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts	0.2	0.1
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	0.1	0.3
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits	1.6	4.5
Deferred Tax Assets, Other	1.4	1.2
Deferred Tax Assets, Gross	33.4	32
Deferred Tax Assets, Valuation Allowance	-2.3	-4.1
Deferred Tax Assets, Net of Valuation Allowance	31.1	27.9
Deferred Tax Liabilities, Unrealized Gains on Trading Securities	1.3	3.1
Deferred Tax Liabilities, Prepaid Expenses	0.9	1.1
Deferred Tax Liabilities, Property, Plant and Equipment	3.4	3.8
Deferred Tax Liabilities, Gross	5.6	8
Deferred Tax Assets, Net	$25.50	$19.90

Income_Taxes_FIN_48_Analysis_D

Income Taxes FIN 48 Analysis (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Abstract]	'	'	'
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	($0.20)	$0.30	$0.20
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]	'	'	'
Balance beginning of year	0.5	0.9	0
Gross increases for tax positions related to current year	0.1	0	0
Gross increases for tax positions related to prior years	0	0	0.9
Gross decreases for tax positions of prior years	-0.2	-0.1	0
Settlements	-0.2	-0.1	0
Lapse of statute of limitations	-0.1	-0.2	0
Balance end of year	$0.10	$0.50	$0.90

Acquisitions_and_Disposals_Det

Acquisitions and Disposals (Details) (USD $)

9 Months Ended

12 Months Ended

1 Months Ended

0 Months Ended

1 Months Ended

12 Months Ended

13 Months Ended

1 Months Ended

12 Months Ended

In Millions, except Share data, unless otherwise specified

Jun. 30, 2013

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Feb. 28, 2013

Sep. 30, 2013

Apr. 30, 2010

Nov. 30, 2012

Nov. 30, 2011

Nov. 25, 2012

Apr. 30, 2012

Feb. 29, 2012

Oct. 31, 2011

Apr. 30, 2011

Aug. 31, 2011

Sep. 30, 2010

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Dec. 12, 2012

Oct. 31, 2011

Oct. 31, 2011

Oct. 31, 2011

Sep. 30, 2013

Sep. 30, 2013

business

business

Tradewire Acquisition [Member] [Member]

Tradewire Acquisition [Member] [Member]

Coffee Network Acquisition [Member]

Coffee Network Acquisition [Member]

MF Metals Team Acquisition [Member]

TRX Futures Acquisition [Member]

DTVM Acquisition [Member]

Hencorp Acquisition [Member]

Hudson Capital Asset Acquisition [Member]

Arabian Commodities Limited [Member]

Provident Group Asset Acquisition [Member]

Provident Group Asset Acquisition [Member]

Provident Group Asset Acquisition [Member]

Provident Group Asset Acquisition [Member]

Customer Relationships [Member]

Customer Relationships [Member]

Noncompete Agreements [Member]

Trade Names [Member]

Tradewire Acquisition [Member] [Member]

INTL Commodities - Physical Base Metals [Domain]

payment

professional

payment

Tradewire Acquisition [Member] [Member]

Hencorp Acquisition [Member]

Hencorp Acquisition [Member]

Hencorp Acquisition [Member]

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Contingent Consideration, Potential Cash Payment

'

'

'

'

'

'

'

'

'

'

'

'

$0.70

'

'

'

'

'

'

'

'

'

'

'

'

Number of Businesses Acquired

'

3

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Goodwill, Expected Tax Deductible Amount

'

5.6

0.7

4.9

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Percentage of Voting Interests Acquired

'

'

'

'

'

'

'

'

100.00%

'

100.00%

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Cost of Acquired Entity, Cash Paid, Payment 1

'

'

'

'

'

'

'

'

0.2

'

'

'

2.3

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Contingent Consideration Arrangements, Number of Annual Payments

'

'

'

'

'

'

'

'

3

'

'

'

2

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Consideration Transferred

'

'

'

'

'

'

'

'

0.3

'

12.9

1.5

'

1

7.1

5

'

'

'

'

'

'

'

5.6

'

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Amortizable Intangibles

'

'

'

'

'

'

'

'

0.2

0.5

'

'

1.7

'

'

'

'

'

'

'

1.3

0.4

'

'

'

Acquired Finite-lived Intangible Assets, Weighted Average Useful Life

'

'

'

'

'

'

'

'2 years

'

'3 years

'

'

'

'

'

'

'

'

'

'

'20 years

'2 years

'

'

'

Business Combination, Professionals Hired From Acquiree Company

'

'

'

'

'

'

'

'

'

50

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangibles

'

'

'

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Goodwill

'

47.5

44.7

'

'

'

2.8

'

'

'

0.3

0.8

2.1

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Cost of Acquired Entity, Number of Payments

'

'

'

'

'

'

'

'

'

'

'

'

2

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Cost of Acquired Entity, Total of Payments 2 and 3

'

'

'

'

'

'

'

'

'

'

'

'

1.4

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Consideration, Including Contingent Consideration

'

'

'

'

'

6.3

'

'

'

'

'

'

7.5

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Cost of Acquired Entity, Cash Paid, Payment 4

'

'

'

'

'

'

'

'

'

'

'

'

0.3

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangibles Not Amortizable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.8

'

'

Business Combination, Cost of Acquired Entity, Equity Interest Issued or Issuable, Total Shares Purchased and Placed In Escrow

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

214,325

'

'

'

'

'

'

Business Combination, Cost of Acquired Entity, Equity Interest Issued or Issuable, Period From Date of Closing Over Which Shares Will be Released from Escrow

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'5 years

'

'

'

'

'

'

'

'

'

Business Combination, Cost of Acquired Entity, Equity Interest Issued or Issuable, Shares Released from Escrow

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6,799

3,255

'

'

'

'

'

'

'

Acquired Finite-lived Intangible Asset, Amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2.8

'

'

'

'

'

Significant Acquisitions and Disposals, Acquisition Costs or Sale Proceeds

0.8

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Assets of Disposal Group, Including Discontinued Operation

'

'

'

'

0.6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, before Tax

-0.1

-0.1

0

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Exit Costs

'

1.9

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest

'

$22.60

$15.80

$55.40

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$1.40

Discontinued_Operations_Discon

Discontinued Operations Discontinued Operations (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Jan. 01, 2010
				Agora-X, LLC [Member]	Agora-X, LLC [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'
Noncontrolling Interest, Ownership Percentage by Parent	'	'	'	'	15.00%
Gain (Loss) on Sale of Business	$0.40	$0	$0	$0.20	'

Quarterly_Financial_Informatio2

Quarterly Financial Information (Unaudited) Quarterly Financial Information (Unaudited) (Details) (USD $)	12 Months Ended			3 Months Ended								12 Months Ended		3 Months Ended							12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2012	Sep. 30, 2011	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2012	Sep. 30, 2011
				As Reported [Member]	As Reported [Member]	As Reported [Member]	As Reported [Member]	As Reported [Member]	As Reported [Member]	As Reported [Member]	As Reported [Member]	As Reported [Member]	As Reported [Member]	As Restated [Member]	As Restated [Member]	As Restated [Member]	As Restated [Member]	As Restated [Member]	As Restated [Member]	As Restated [Member]	As Restated [Member]	As Restated [Member]
Total revenues	$43,768.30	$67,959.30	$72,891.30	$9,030.40	$11,039.50	$13,113.10	$12,719.50	$17,668.10	$17,351.10	$16,951	$17,290.40	$69,260.60	$75,497.60	$9,996.60	$12,188.50	$12,552.80	$17,369.10	$17,192.90	$16,808	$16,589.30	$67,959.30	$72,891.30
Cost of sales of physical commodities	43,289.90	67,505.10	72,472.20	8,917.80	10,917.40	12,995.80	12,593.80	17,550.10	17,227.30	16,831.40	17,194.10	68,802.90	75,074.40	9,873.80	12,071.20	12,427.10	17,251.20	17,071.40	16,689.50	16,493	67,505.10	72,472.20
Operating revenues	478.4	454.2	419.1	112.6	122.1	117.3	125.7	118	123.8	119.6	96.3	457.7	423.2	122.8	117.3	125.7	117.9	121.5	118.5	96.3	454.2	419.1
Floor Brokerage, Exchange and Clearance Fees	110.1	105.4	75.6	28	28.9	28.6	24.6	26	30.3	26.9	22.2	'	'	28.9	28.6	24.6	26	30.3	26.9	22.2	'	'
Introducing broker commissions	40.5	31	24	11.5	11	9.6	8.4	9.3	7.9	8	5.8	'	'	11	9.6	8.4	9.3	7.9	8	5.8	'	'
Interest expense	12.5	11.6	11.3	2.9	3.2	2.9	3.5	3.3	2.6	3.6	2.1	'	'	3.2	2.9	3.5	3.3	2.6	3.6	2.1	'	'
Net operating revenues	315.3	306.2	308.2	70.2	79	76.2	89.2	79.4	83	81.1	66.2	309.7	312.3	79.7	76.2	89.2	79.3	80.7	80	66.2	306.2	308.2
Compensation and other expenses	292.7	290.4	252.8	72.7	74.9	74.8	70.4	68.9	77.1	77.5	66.9	'	'	74.8	74.8	70.4	68.9	77.1	77.5	66.9	'	'
Income from continuing operations, before tax	22.6	15.8	55.4	-2.5	4.1	1.4	18.8	10.5	5.9	3.6	-0.7	19.3	59.5	4.9	1.4	18.8	10.4	3.6	2.5	-0.7	15.8	55.4
Income tax expense	3.3	3.1	20.9	-3.7	1.3	-0.1	5.5	2.2	1.2	1.2	-0.2	4.4	22.5	1.6	-0.1	5.5	2.1	0.4	0.8	-0.2	3.1	20.9
Net income	19.3	12.7	34.5	1.2	2.8	1.5	13.3	8.3	4.7	2.4	-0.5	'	'	3.3	1.5	13.3	8.3	3.2	1.7	-0.5	'	'
Net Income (Loss) Attributable to Noncontrolling Interest	0	0.1	0.1	'	'	'	'	0	0	0	0.1	'	'	'	'	'	0	0	0	0.1	'	'
Net Income (Loss) Attributable to Parent	$19.30	$12.80	$34.80	'	'	'	'	$8.30	$4.70	$2.40	($0.40)	$15	$37.30	'	'	'	$8.30	$3.20	$1.70	($0.40)	$12.80	$34.80
Net basic earnings per share	$1.01	$0.67	$1.93	$0.05	$0.15	$0.08	$0.70	$0.44	$0.24	$0.13	($0.02)	$0.79	$2.07	$0.18	$0.08	$0.70	$0.44	$0.16	$0.09	($0.02)	$0.67	$1.93
Net diluted earnings per share	$0.97	$0.64	$1.83	$0.04	$0.15	$0.08	$0.68	$0.42	$0.23	$0.12	($0.02)	$0.75	$1.96	$0.17	$0.08	$0.68	$0.42	$0.15	$0.09	($0.02)	$0.64	$1.83

Segment_and_Geographic_Informa2

Segment and Geographic Information - Reportable Segments (Details)	12 Months Ended
	Sep. 30, 2013
Segment Analysis [Abstract]	'
Number of different types of foreign currencies	130

Segment_and_Geographic_Informa3

Segment and Geographic Information (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Segment Reporting Information [Line Items]	'	'	'
Revenues	$43,768.30	$67,959.30	$72,891.30
Operating revenues	478.4	454.2	419.1
Net Contribution	234.1	225.2	225.4
Net Segment Income	114.3	106.6	129.8
Costs not allocated	91.7	90.8	74.4
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	22.6	15.8	55.4
Assets	2,848	2,953	2,632
Commodity and Risk Management [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	43,218.20	67,627	72,667.80
Operating revenues	221.7	242.5	248.5
Net Contribution	131.1	139.5	147.5
Net Segment Income	59.6	66.2	89.4
Assets	1,105.10	1,439.70	1,534.80
Foreign Exchange Segment [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	66.9	62.6	59.3
Operating revenues	66.9	62.6	59.3
Net Contribution	44	41.3	37.1
Net Segment Income	29.8	28.3	28
Assets	145	124.5	146.1
Securities Segment [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	61.1	39.9	30.5
Operating revenues	61.1	39.9	30.5
Net Contribution	30.5	19.8	16.5
Net Segment Income	13.9	4.5	1.9
Assets	198.5	88.7	104.8
Clearing and Execution Services Segment [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	100.8	93.8	66.1
Operating revenues	100.8	93.8	66.1
Net Contribution	15.3	14.3	14.3
Net Segment Income	1.9	2.2	4.9
Assets	1,246.40	1,090.90	734.4
Other Segment [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	314.1	136.2	67.2
Operating revenues	20.7	15.6	14.3
Net Contribution	13.2	10.3	10
Net Segment Income	9.1	5.4	5.6
Assets	37.3	110.8	43.4
Corporate [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	7.2	-0.2	0.4
Operating revenues	7.2	-0.2	0.4
Assets	$115.70	$98.40	$68.50

Segment_and_Geographic_Informa4

Segment and Geographic Information Total Revenues by Geographic Location (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Revenues	$43,768.30	$67,959.30	$72,891.30
Gross Profit	478.4	454.2	419.1
Long-Lived Assets	17.5	18.9	15
UNITED STATES	'	'	'
Revenues	29,062	53,398	48,165.30
Gross Profit	333.9	293.8	298
Long-Lived Assets	9.1	11.5	10.7
Europe [Member]	'	'	'
Revenues	65.6	69.9	35.1
Gross Profit	65.6	69.9	35.1
Long-Lived Assets	5.4	3.8	2
South America [Member]	'	'	'
Revenues	51.3	58.2	53.3
Gross Profit	51.3	58.2	53.3
Long-Lived Assets	2.4	2.8	1.6
Asia [Member]	'	'	'
Revenues	14,582.10	14,420.80	24,627
Gross Profit	20.3	19.9	27.6
Long-Lived Assets	0.5	0.7	0.6
Other (geographic location) [Member]	'	'	'
Revenues	7.3	12.4	10.6
Gross Profit	7.3	12.4	5.1
Long-Lived Assets	$0.10	$0.10	$0.10

Condensed_Parent_Only_Financia2

Condensed Parent Only Financial Statements [Schedule] Balance Sheet (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
In Millions, unless otherwise specified
Cash and cash equivalents	$156.10	$236.30	$220.60	$81.90
Income taxes receivable	15.5	15.5	'	'
Financial instruments, owned, at fair value	158.5	171.7	'	'
Deferred Tax Assets, Net	25.5	19.9	'	'
Property and equipment, net	17.5	18.9	'	'
Goodwill and intangible assets, net	59.1	55.8	'	'
Total assets	2,848	2,953	2,632	'
Liabilities:	'	'	'	'
Accounts payable and other accrued liabilities	114	127	'	'
Payables to Customers	2,091.80	2,072.30	'	'
Payables to lenders under loans	61	218.2	'	'
Senior unsecured notes	45.5	0	'	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	179.9	175.4	'	'
Total liabilities	2,512.60	2,639.80	'	'
INTL FCStone Inc. (Parent Company Only) stockholders’ equity:	'	'	'	'
Common stock, $.01 par value. Authorized 30,000,000 shares; 19,638,330 issued and 19,209,157 outstanding at September 30, 2013 and 19,214,219 issued and 18,984,951 outstanding at September 30, 2012	0.2	0.2	'	'
Common stock in treasury, at cost - 429,173 shares at September 30, 2013 and 229,064 shares at September 30, 2012	-7.8	-4.1	'	'
Additional Paid in Capital	224	213.2	'	'
Retained earnings	125.4	106.1	'	'
Accumulated other comprehensive loss	-6.4	-2.2	'	'
Total INTL FCStone Inc. (Parent Company Only) stockholders’ equity	335.4	313.2	'	'
Total liabilities and equity	2,848	2,953	'	'
Parent Company [Member]	'	'	'	'
Cash and cash equivalents	3.1	13.1	2	0.4
Receivables from subsidiaries	22.9	20.1	'	'
Notes receivable, net	27.3	10.2	'	'
Income taxes receivable	17.5	14.3	'	'
Financial instruments, owned, at fair value	0	1.5	'	'
Investment in subsidiaries	237.3	220.1	'	'
Deferred Tax Assets, Net	7.1	0.9	'	'
Property and equipment, net	3.6	4.3	'	'
Goodwill and intangible assets, net	0	0	'	'
Other assets	4.3	3.4	'	'
Total assets	323.1	287.9	'	'
Adjustment to Investment in Subs for Equity Method Accounting	149.6	105.7	'	'
Adjustment to Retained Earnings for Equity Method	155.2	111.6	'	'
Liabilities:	'	'	'	'
Accounts payable and other accrued liabilities	11.1	4.2	'	'
Payables to Customers	18.7	0.7	'	'
Payables to lenders under loans	55	48	'	'
Financial Instruments Sold, Not yet Purchased, at Fair Value	0.6	25.3	'	'
Total liabilities	130.9	78.2	'	'
INTL FCStone Inc. (Parent Company Only) stockholders’ equity:	'	'	'	'
Preferred stock, $.01 par value. Authorized 1,000,000 shares; no shares issued or outstanding	0	0	'	'
Common stock, $.01 par value. Authorized 30,000,000 shares; 19,638,330 issued and 19,209,157 outstanding at September 30, 2013 and 19,214,219 issued and 18,984,951 outstanding at September 30, 2012	0.2	0.2	'	'
Common stock in treasury, at cost - 429,173 shares at September 30, 2013 and 229,064 shares at September 30, 2012	7.8	4.1	'	'
Additional Paid in Capital	224	213.2	'	'
Retained earnings	-24.2	0.4	'	'
Total INTL FCStone Inc. (Parent Company Only) stockholders’ equity	192.2	209.7	'	'
Total liabilities and equity	$323.10	$287.90	'	'

Condensed_Parent_Only_Financia3

Condensed Parent Only Financial Statements [Schedule] Income Statement (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Condensed Financial Statements, Captions [Line Items]	'	'	'
Trading gains, net	$265	$244.90	$201.60
Commission and clearing fees	173.3	161	134.5
Interest income	10.3	10.3	10.3
Other Income	0.9	0.5	1
Operating revenues	478.4	454.2	419.1
Interest expense	12.5	11.6	11.3
Net operating revenues	315.3	306.2	308.2
Non-interest expenses:	'	'	'
Compensation and benefits	201.6	202.4	176.6
Clearing and related expenses	110.1	105.4	75.6
Introducing broker commissions	40.5	31	24
Communication and data services	23.3	22.6	15.5
Occupancy and equipment rental	12	11	8.9
Professional fees	13.1	12.9	10.6
Travel and business development	10.7	11.2	8.9
Depreciation and amortization	8	7.2	4.7
Bad debts and impairments	0.8	1.5	6.2
Other	23.2	21.6	21.4
Total compensation and other expenses	292.7	290.4	252.8
Income from continuing operations, before tax	22.6	15.8	55.4
Income tax benefit	-3.3	-3.1	-20.9
Net income attributable to INTL FCStone Inc. common stockholders	19.3	12.8	34.8
Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Trading gains, net	7.2	7.1	3.1
Commission and clearing fees	1.6	0.2	0
Interest income	3.6	2.1	4.3
Other Income	2	0.1	0.4
Operating revenues	14.4	9.5	7.8
Interest expense	7.1	5.6	9.7
Net operating revenues	7.3	3.9	-1.9
Non-interest expenses:	'	'	'
Compensation and benefits	30.5	12.4	8.6
Clearing and related expenses	0.5	0.3	0.1
Introducing broker commissions	0.5	0	0.2
Communication and data services	0.9	0.6	0.5
Occupancy and equipment rental	1.4	1	1.2
Professional fees	2.3	3.1	3.8
Travel and business development	1.2	1.4	0.5
Depreciation and amortization	1.5	1.2	0.6
Bad debts and impairments	0	2.2	0
Other	6.3	5.4	-1
Total compensation and other expenses	45.1	27.6	14.5
Income from continuing operations, before tax	-37.8	-23.7	-16.4
Income tax benefit	13.2	9.2	6.4
Net income attributable to INTL FCStone Inc. common stockholders	-24.6	-14.5	-10
Adjustment to Investment in Subs for Equity Method Accounting	$43.90	$27.30	$44.80

Condensed_Parent_Only_Financia4

Condensed Parent Only Financial Statements [Schedule] Cash Flows (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Condensed Financial Statements, Captions [Line Items]	'	'	'
Net income attributable to INTL FCStone Inc. common stockholders	$19.30	$12.80	$34.80
Depreciation, Depletion and Amortization, Nonproduction	8	7.2	4.7
Deferred Income Tax Expense (Benefit)	-7.7	-0.5	1.8
Amortization of Financing Costs and Discounts	1.2	1.7	1.6
Convertible debt interest settled in company stock upon conversion	0	0	0.2
Share-based Compensation	9.3	5.9	2.3
Gain on acquisition of INTL Provident	0	0	-0.4
Notes receivable, net	66.6	-77.9	2.9
Income taxes receivable	-0.2	-3.1	0.6
Financial instruments owned, at fair value	3.1	58.3	280.7
Other assets	4.3	-1.6	-12.1
Increase (Decrease) in Accounts Payable and Accrued Liabilities	-0.2	10.6	30.8
Increase (Decrease) in Payables to Customers	24	248	366.2
Increase (Decrease) in Financial Instruments Sold, Not yet Purchased	4.6	-215.5	202.9
Net Cash Provided by (Used in) Operating Activities	44.9	-92.1	209
Cash paid for other acquisitions, net	0	-11.7	-9.3
Payments to Acquire Property, Plant, and Equipment	-4.9	-8.7	-10.1
Net Cash Provided by (Used in) Investing Activities	5.1	-20	-21.5
Net change in payable to lenders under loans	-157.2	140.8	-37.5
Proceeds from Issuance of Senior Long-term Debt	45.5	0	0
Share repurchase	-3.9	-4	0
Debt issuance costs	-3.7	-0.3	-2.4
Exercise of stock options	1.5	1.9	1.4
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	0.1	0.2	0
Net Cash Provided by (Used in) Financing Activities	-129.7	129	-48.4
Cash and Cash Equivalents, Period Increase (Decrease)	-80.2	15.7	138.7
Cash and Cash Equivalents, at Carrying Value	156.1	236.3	220.6
Cash paid for interest	8.9	7.9	9.5
Income taxes paid, net of cash refunds	10.2	6.1	17.6
Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Net income attributable to INTL FCStone Inc. common stockholders	-24.6	-14.5	-10
Depreciation, Depletion and Amortization, Nonproduction	1.5	1.2	0.6
Tangible Asset Impairment Charges	0	2.2	0
Deferred Income Tax Expense (Benefit)	-6.1	-0.1	1.1
Amortization of Financing Costs and Discounts	0.5	0.5	0.2
Convertible debt interest settled in company stock upon conversion	0	0	0.2
Share-based Compensation	9.3	5.9	2.3
Gain on acquisition of INTL Provident	0	0	-0.4
Increase (Decrease) Due from Affiliates	-2.8	21.7	35.7
Notes receivable, net	-17.1	-10.2	0
Income taxes receivable	-3.2	7.1	-13.6
Financial instruments owned, at fair value	1.5	1.7	-0.4
Other assets	1.7	-0.3	-0.8
Increase (Decrease) in Accounts Payable and Accrued Liabilities	1.4	-2.2	1.7
Increase (Decrease) in Payables to Customers	18	0.7	0
Increase (Decrease) in Financial Instruments Sold, Not yet Purchased	-24.7	-33.4	-0.5
Net Cash Provided by (Used in) Operating Activities	-44.6	-19.7	16.1
Payments for Advance to Affiliate	-11.5	-12.5	-1
Payments to Acquire Property, Plant, and Equipment	-0.8	-2.7	-1.7
Net Cash Provided by (Used in) Investing Activities	-12.3	-15.2	-2.7
Net change in payable to lenders under loans	7	48	-11.9
Proceeds from Issuance of Senior Long-term Debt	45.5	0	0
Share repurchase	-4	-4	0
Debt issuance costs	-3.2	-0.1	-1.2
Exercise of stock options	1.5	1.9	1.3
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	0.1	0.2	0
Net Cash Provided by (Used in) Financing Activities	46.9	46	-11.8
Cash and Cash Equivalents, Period Increase (Decrease)	-10	11.1	1.6
Cash and Cash Equivalents, at Carrying Value	3.1	13.1	2
Cash paid for interest	3	2.1	3
Income taxes paid, net of cash refunds	-1.6	0.1	10.8
Convertible note conversions	$0	$0	$16.70