Assets and Liabilities, at Fair Value (Tables)

6 Months Ended

Mar. 31, 2015

Assets and Liabilities, at Fair Value [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

The following tables set forth the Company’s financial and nonfinancial assets and liabilities accounted for at fair value, on a recurring basis, as of March 31, 2015 and September 30, 2014 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 March 31, 2015 and September 30, 2014.

	March 31, 2015
(in millions)	Level 1		Level 2		Level 3		Netting and Collateral (1)			Total
Assets:
Unrestricted cash equivalents - certificate of deposits	$	2.6	$	—	$	—	$	—		$	2.6
Commodities warehouse receipts	16.8		—		—		—			16.8
U.S. government obligations	—		492.2		—		—			492.2
Securities and other assets segregated under federal and other regulations	16.8		492.2		—		—			509.0
Money market funds	251.7		—		—		—			251.7
U.S. government obligations	—		621.5		—		—			621.5
Derivatives	5,146.1		—		—		(5,010.6		)	135.5
Deposits and receivables from exchange-clearing organizations	5,397.8		621.5		—		(5,010.6		)	1,008.7
Foreign government obligations	—		1.2		—		—			1.2
Derivatives	399.5		1.1		—		(430.4		)	(29.8		)
Deposits and receivables from broker-dealers, clearing organizations and counterparties - derivatives	399.5		2.3		—		(430.4		)	(28.6		)
Common and preferred stock and American Depositary Receipts (“ADRs”)	98.2		10.0		0.5		—			108.7
Exchangeable foreign ordinary equities and ADRs	8.1		—		—		—			8.1
Corporate and municipal bonds	8.3		3.1		3.6		—			15.0
U.S. government obligations	—		458.9		—		—			458.9
Foreign government obligations	—		10.4		—		—			10.4
Derivatives	322.7		1,988.1		—		(2,258.7		)	52.1
Commodities leases	—		82.8		—		(81.2		)	1.6
Exchange firm common stock	5.7		—		—		—			5.7
Mutual funds and other	2.4		—		—		—			2.4
Mortgage-backed securities	—		554.2		—		—			554.2
Financial instruments owned	445.4		3,107.5		4.1		(2,339.9		)	1,217.1
Total assets at fair value	$	6,262.1	$	4,223.5	$	4.1	$	(7,780.9	)	$	2,708.8
Liabilities:
Accounts payable and other accrued liabilities - contingent liabilities	$	—	$	—	$	3.1	$	—		$	3.1
Payable to broker-dealers, clearing organizations and counterparties - derivatives	5,294.9		2.6		—		(5,296.0		)	1.5
Common and preferred stock and ADRs	108.8		1.2		—		—			110.0
Exchangeable foreign ordinary equities and ADRs	10.8		—		—		—			10.8
U.S. government obligations	—		327.3		—		—			327.3
Mortgage-backed securities	—		0.5		—		—			0.5
Derivatives	311.9		2,006.4		—		(2,236.3		)	82.0
Commodities leases	—		92.4		—		(9.7		)	82.7
Financial instruments sold, not yet purchased	431.5		2,427.8		—		(2,246.0		)	613.3
Total liabilities at fair value	$	5,726.4	$	2,430.4	$	3.1	$	(7,542.0	)	$	617.9

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

	September 30, 2014
(in millions)	Level 1		Level 2		Level 3		Netting and Collateral (1)			Total
Assets:
Unrestricted cash equivalents - certificates of deposits	$	1.5	$	—	$	—	$	—		$	1.5
Commodities warehouse receipts	14.8		—		—		—			14.8
U.S. government obligations	—		0.5		—		—			0.5
Securities and other assets segregated under federal and other regulations	14.8		0.5		—		—			15.3
Money market funds	826.8		—		—		—			826.8
U.S. government obligations	—		702.5		—		—			702.5
Derivatives	3,397.1		—		—		(3,671.0		)	(273.9		)
Deposits and receivables from exchange-clearing organizations	4,223.9		702.5		—		(3,671.0		)	1,255.4
Deposits and receivables from broker-dealers, clearing organizations and counterparties - derivatives	549.0		—		—		(550.1		)	(1.1		)
Common and preferred stock and American Depositary Receipts (“ADRs”)	66.8		15.0		0.7		—			82.5
Exchangeable foreign ordinary equities and ADRs	27.2		—		—		—			27.2
Corporate and municipal bonds	7.1		9.0		3.6		—			19.7
U.S. government obligations	—		0.3		—		—			0.3
Foreign government obligations	—		10.7		—		—			10.7
Derivatives	332.4		2,328.3		—		(2,616.4		)	44.3
Commodities leases	—		60.1		—		(58.0		)	2.1
Commodities warehouse receipts	3.6		—		—		—			3.6
Exchange firm common stock	4.8		—		—		—			4.8
Mutual funds and other	2.7		—		—		—			2.7
Financial instruments owned	444.6		2,423.4		4.3		(2,674.4		)	197.9
Total assets at fair value	$	5,233.8	$	3,126.4	$	4.3	$	(6,895.5	)	$	1,469.0
Liabilities:
Accounts payable and other accrued liabilities - contingent liabilities	$	—	$	—	$	5.5	$	—		$	5.5
Payable to broker-dealers, clearing organizations and counterparties - derivatives	3,469.8		—		—		(3,469.8		)	—
Common and preferred stock and ADRs	92.8		2.6		—		—			95.4
Exchangeable foreign ordinary equities and ADRs	5.8		—		—		—			5.8
Corporate and municipal bonds	2.8		—		—		—			2.8
Derivatives	327.0		2,257.7		—		(2,500.3		)	84.4
Commodities leases	—		176.0		—		(100.4		)	75.6
Financial instruments sold, not yet purchased	428.4		2,436.3		—		(2,600.7		)	264.0
Total liabilities at fair value	$	3,898.2	$	2,436.3	$	5.5	$	(6,070.5	)	$	269.5

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

Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

Information on Level 3 Financial Assets and Liabilities

The Company’s financial assets at fair value classified in level 3 of the fair value hierarchy as of March 31, 2015 and September 30, 2014 are summarized below:

(in millions)	March 31, 2015			September 30, 2014
Total level 3 assets	$	4.1		$	4.3
Level 3 assets for which the Company bears economic exposure	$	4.1		$	4.3
Total assets	$	4,462.6		$	3,039.7
Total financial assets at fair value	$	2,708.8		$	1,469.0
Total level 3 assets as a percentage of total assets	0.1		%	0.1		%
Level 3 assets for which the Company bears economic exposure as a percentage of total assets	0.1		%	0.1		%
Total level 3 assets as a percentage of total financial assets at fair value	0.2		%	0.3		%

The following tables set forth a summary of changes in the fair value of the Company’s level 3 financial assets and liabilities during the three months ended March 31, 2015 and 2014, including a summary of unrealized gains (losses) during the respective periods on the Company’s level 3 financial assets and liabilities still held as of March 31, 2015.

	Level 3 Financial Assets and Financial Liabilities For the Three Months Ended March 31, 2015
(in millions)	Balances at beginning of period		Realized gains (losses) during period		Unrealized gains (losses) during period			Purchases/issuances		Settlements			Transfers in or (out) of Level 3		Balances at end of period
Assets:
Common stock and ADRs	$	0.6	$	—	$	(0.1	)	$	—	$	—		$	—	$	0.5
Corporate and municipal bonds	3.5		—		0.1			—		—			—		3.6
	$	4.1	$	—	$	—		$	—	$	—		$	—	$	4.1
Liabilities:
Contingent liabilities	$	2.2	$	—	$	0.1		$	1.5	$	(0.7	)	$	—	$	3.1

	Level 3 Financial Assets and Financial Liabilities For the Six Months Ended March 31, 2015
(in millions)	Balances at beginning of period		Realized gains (losses) during period		Unrealized gains (losses) during period			Purchases/issuances		Settlements			Transfers in or (out) of Level 3		Balances at end of period
Assets:
Common stock and ADRs	$	0.7	$	—	$	(0.2	)	$	—	$	—		$	—	$	0.5
Corporate and municipal bonds	3.6		—		—			—		—			—		3.6
	$	4.3	$	—	$	(0.2	)	$	—	$	—		$	—	$	4.1
Liabilities:
Contingent liabilities	$	5.5	$	—	$	0.2		$	1.5	$	(4.1	)	$	—	$	3.1

	Level 3 Financial Assets and Financial Liabilities For the Three Months Ended March 31, 2014
(in millions)	Balances at beginning of period		Realized gains (losses) during period		Unrealized gains (losses) during period		Purchases/issuances		Settlements		Transfers in or (out) of Level 3		Balances at end of period
Assets:
Common stock and ADRs	$	0.7	$	—	$	—	$	—	$	—	$	—	$	0.7
Corporate and municipal bonds	3.4		—		—		—		—		—		3.4
	$	4.1	$	—	$	—	$	—	$	—	$	—	$	4.1
Liabilities:
Contingent liabilities	$	9.1	$	—	$	0.1	$	—	$	—	$	—	$	9.2

	Level 3 Financial Assets and Financial Liabilities For the Six Months Ended March 31, 2014
(in millions)	Balances at beginning of period		Realized gains (losses) during period		Unrealized gains (losses) during period			Purchases/issuances		Settlements			Transfers in or (out) of Level 3		Balances at end of period
Assets:
Common stock and ADRs	$	0.7	$	—	$	—		$	—	$	—		$	—	$	0.7
Corporate and municipal bonds	3.5		—		(0.1		)	—		—			—		3.4
	$	4.2	$	—	$	(0.1	)	$	—	$	—		$	—	$	4.1
Liabilities:
Contingent liabilities	$	9.6	$	—	$	0.3		$	—	$	(0.7	)	$	—	$	9.2

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 March 31, 2015 and September 30, 2014:

March 31, 2015
Amounts included in deposits with and receivables from exchange-clearing organizations and securities segregated:
	Amortized Cost		Unrealized Holding				Estimated Fair Value
(in millions)			Gains		(Losses)
U.S. government obligations	$	1,076.7	$	4.5	$	—	$	1,081.2

September 30, 2014
Amounts included in deposits with and receivables from exchange-clearing organizations:
	Amortized Cost		Unrealized Holding(1)				Estimated Fair Value
(in millions)			Gains		(Losses)
U.S. government obligations	$	666.8	$	—	$	—	$	666.8

(1) Unrealized gain/loss on U.S. government obligations as of September 30, 2014, was less than $0.1 million.

As of March 31, 2015 and September 30, 2014, investments in debt securities classified as available-for-sale (“AFS”) mature as follows:

March 31, 2015
	Due in				Estimated Fair Value
(in millions)	Less than 1 year		1 year or more
U.S. government obligations	$	398.5	$	682.7	$	1,081.2

September 30, 2014
	Due in				Estimated Fair Value
(in millions)	Less than 1 year		1 year or more
U.S. government obligations	$	287.6	$	379.2	$	666.8

There were no sales of AFS securities during the three months ended March 31, 2015 and 2014, and as a result, no realized gains or losses were recorded for the three months ended March 31, 2015 and 2014.

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.