Credit Facilities Level 4 - Credit Facilities (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Jun. 30, 2012	Sep. 30, 2011
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding	$ 175.4	$ 77.4
Lines of Credit, to expire before the end of the fiscal year	140
Main line of credit facilities [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	335.0
Line of credit for uncommited forward contracts [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	50.0
INTL COM line of credit facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Collateral	Certain commodities assets
Line of Credit Facility, Expiration Date	Sep. 20, 2012
Line of Credit Facility, Maximum Borrowing Capacity	140.0
Line of Credit Facility, Amount Outstanding	97.0	60.0
HCO Syndicated line of credit facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Collateral	Certain pledged shares
Line of Credit Facility, Expiration Date	Oct. 01, 2013
Line of Credit Facility, Maximum Borrowing Capacity	95.0
Line of Credit Facility, Amount Outstanding	70.0	0
FCS Margin line of credit facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Collateral	None
Line of Credit Facility, Expiration Date	Apr. 11, 2013
Line of Credit Facility, Maximum Borrowing Capacity	75.0
Line of Credit Facility, Amount Outstanding	0	0
FCF Sub-note commodity line of credit facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Collateral	Certain commodities assets
Line of Credit Facility, Expiration Date	Oct. 09, 2012
Line of Credit Facility, Maximum Borrowing Capacity	25.0
Line of Credit Facility, Amount Outstanding	8.4	15.5
FCF Sub-note commodity line of credit facility - Original [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	75.0
FCF Sub-note commodity line of credit facility - Revised [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	25.0
FCF Sub-note commodity line of credit facility - subsequent revision [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	50.0
FMS line of credit for uncommited forward contracts [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Collateral	Certain forward commodity contracts
Line of Credit Facility, Maximum Borrowing Capacity	50.0
Uncommited Forward Contract for Commodities Line of Credit, Maximum Committment Amount	0
Line of Credit Facility, Amount Outstanding	$ 0	$ 1.9