Basis of Presentation and Consolidation and Recently Issued Accounting Standards (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Basis of Presentation and Consolidation [Abstract]
Number of different types of foreign currencies			150
Number of accounts for customers company-wide			20,000
Number of customers company-wide			11,000
Statement [Line Items]
Trading gains, net	$ 61.6	$ 60.2	$ 178.0	$ 186.5
Total compensation and other expenses	72.0	74.2	217.1	216.9
Sales of physical commodities	6,886.6	9,540.5	23,017.2	33,215.7
Cost of sales of physical commodities	6,886.9	9,536.1	23,006.4	33,209.6
Scenario, Previously Reported [Member]
Statement [Line Items]
Sales of physical commodities		11,039.5		36,872.1
Cost of sales of physical commodities		10,917.4		36,507.0
Scenario, Adjustment [Member]
Statement [Line Items]
Total compensation and other expenses		0.1
Net Income				0.5
Sales of physical commodities		(1,043.6)		(2,134.9)
Cost of sales of physical commodities		(1,043.6)		(2,134.9)
Restatement Adjustment [Member]
Statement [Line Items]
Trading gains, net		0.7
Sales of physical commodities		9,995.9		34,737.2
Cost of sales of physical commodities		$ 9,873.8		$ 34,372.1