Assets and Liabilities, at Fair Value (Tables)

6 Months Ended

Mar. 31, 2017

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, 2017 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, 2017.

	March 31, 2017
(in millions)	Level 1		Level 2		Level 3		Netting and Collateral (1)			Total
Assets:
Unrestricted cash equivalents - certificate of deposits	$	3.4	$	—	$	—	$	—		$	3.4
Commodities warehouse receipts	21.9		—		—		—			21.9
U.S. government obligations	—		225.7		—		—			225.7
Securities and other assets segregated under federal and other regulations	21.9		225.7		—		—			247.6
Money market funds	376.0		—		—		—			376.0
U.S. government obligations	—		281.8		—		—			281.8
Derivatives	1,799.0		—		—		(1,820.3		)	(21.3		)
Deposits with and receivables from exchange-clearing organizations	2,175.0		281.8		—		(1,820.3		)	636.5
"To be announced" (TBA) and forward settling securities	—		6.2		—		(0.9		)	5.3
Derivatives	—		89.2		—		(59.8		)	29.4
Deposits with and receivables from broker-dealers, clearing organizations and counterparties	—		95.4		—		(60.7		)	34.7
Common and preferred stock and ADRs	28.5		2.0		0.2		—			30.7
Exchangeable foreign ordinary equities and ADRs	31.3		0.4		—		—			31.7
Corporate and municipal bonds	4.9		1.3		—		—			6.2
U.S. government obligations	—		625.4		—		—			625.4
Foreign government obligations	—		49.4		—		—			49.4
Mortgage-backed securities	—		926.6		—		—			926.6
Derivatives	266.4		1,419.0		—		(1,487.0		)	198.4
Commodities leases	—		117.2		—		(100.0		)	17.2
Commodities warehouse receipts	8.0		—		—		—			8.0
Exchange firm common stock	7.1		—		—		—			7.1
Mutual funds and other	6.0		—		—		—			6.0
Financial instruments owned	352.2		3,141.3		0.2		(1,587.0		)	1,906.7
Physical commodities inventory	117.8		—		—		—			117.8
Total assets at fair value	$	2,670.3	$	3,744.2	$	0.2	$	(3,468.0	)	$	2,946.7
Liabilities:
Accounts payable and other accrued liabilities - contingent liabilities	$	—	$	—	$	0.9	$	—		$	0.9
TBA and forward settling securities	—		10.8		—		(0.9		)	9.9
Derivatives	1,560.8		103.0		—		(1,663.9		)	(0.1		)
Payable to broker-dealers, clearing organizations and counterparties	1,560.8		113.8		—		(1,664.8		)	9.8
Common and preferred stock and ADRs	45.4		0.5		—		—			45.9
Exchangeable foreign ordinary equities and ADRs	31.6		0.3		—		—			31.9
Corporate and municipal bonds	1.2		—		—		—			1.2
U.S. government obligations	—		699.9		—		—			699.9
Foreign government obligations	—		10.1		—		—			10.1
Mortgage-backed securities	—		4.7		—		—			4.7
Derivatives	261.0		1,575.9		—		(1,607.3		)	229.6
Commodities leases	—		164.8		—		(106.9		)	57.9
Financial instruments sold, not yet purchased	339.2		2,456.2		—		(1,714.2		)	1,081.2
Total liabilities at fair value	$	1,900.0	$	2,570.0	$	0.9	$	(3,379.0	)	$	1,091.9

(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.

The following table sets forth the Company’s financial and nonfinancial assets and liabilities accounted for at fair value, on a recurring basis, as of September 30, 2016 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, 2016.

	September 30, 2016
(in millions)	Level 1		Level 2		Level 3		Netting and Collateral (1)			Total
Assets:
Unrestricted cash equivalents - certificates of deposits	$	7.1	$	—	$	—	$	—		$	7.1
Commodities warehouse receipts	23.3		—		—		—			23.3
U.S. government obligations	—		595.5		—		—			595.5
Securities and other assets segregated under federal and other regulations	23.3		595.5		—		—			618.8
Money market funds	512.7		—		—		—			512.7
U.S. government obligations	—		472.1		—		—			472.1
Derivatives	2,149.9		—		—		(2,266.2		)	(116.3		)
Deposits with and receivables from exchange-clearing organizations	2,662.6		472.1		—		(2,266.2		)	868.5
TBA and forward settling securities	—		0.3		—		—			0.3
Derivatives	—		8.0		—		(23.5		)	(15.5		)
Deposits with and receivables from broker-dealers, clearing organizations and counterparties	—		8.3		—		(23.5		)	(15.2		)
Common and preferred stock and ADRs	34.6		1.7		0.2		—			36.5
Exchangeable foreign ordinary equities and ADRs	25.2		0.5		—		—			25.7
Corporate and municipal bonds	36.9		0.9		3.0		—			40.8
U.S. government obligations	—		514.9		—		—			514.9
Foreign government obligations	—		14.6		—		—			14.6
Mortgage-backed securities	—		747.5		—		—			747.5
Derivatives	206.9		1,350.8		—		(1,363.8		)	193.9
Commodities leases	—		137.2		—		(129.1		)	8.1
Commodities warehouse receipts	8.9		—		—		—			8.9
Exchange firm common stock	6.4		—		—		—			6.4
Mutual funds and other	8.8		—		—		—			8.8
Financial instruments owned	327.7		2,768.1		3.2		(1,492.9		)	1,606.1
Physical commodities inventory, net - precious metals	71.2		—		—		—			71.2
Total assets at fair value	$	3,091.9	$	3,844.0	$	3.2	$	(3,782.6	)	$	3,156.5
Liabilities:
Accounts payable and other accrued liabilities - contingent liabilities	$	—	$	—	$	0.8	$	—		$	0.8
TBA and forward settling securities	—		2.6		—		0.9			3.5
Derivatives	1,961.7		97.5		—		(2,059.2		)	—
Payable to broker-dealers, clearing organizations and counterparties	1,961.7		100.1		—		(2,058.3		)	3.5
Common and preferred stock and ADRs	23.5		0.4		—		—			23.9
Exchangeable foreign ordinary equities and ADRs	25.3		0.5		—		—			25.8
U.S. government obligations	—		509.8		—		—			509.8
Corporate and municipal bonds	6.9		—		—		—			6.9
Derivatives	199.4		1,319.3		—		(1,307.8		)	210.9
Commodities leases	—		207.8		—		(145.7		)	62.1
Financial instruments sold, not yet purchased	255.1		2,037.8		—		(1,453.5		)	839.4
Total liabilities at fair value	$	2,216.8	$	2,137.9	$	0.8	$	(3,511.8	)	$	843.7

(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, 2017 and September 30, 2016 are summarized below:

(in millions)	March 31, 2017			September 30, 2016
Total level 3 assets	$	0.2		$	3.2
Level 3 assets for which the Company bears economic exposure	$	0.2		$	3.2
Total assets	$	6,528.6		$	5,950.3
Total assets at fair value	$	2,946.7		$	3,156.5
Total level 3 assets as a percentage of total assets	—		%	0.1		%
Level 3 assets for which the Company bears economic exposure as a percentage of total assets	—		%	0.1		%
Total level 3 assets as a percentage of total financial assets at fair value	—		%	0.1		%

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 and six months ended March 31, 2017 and 2016, 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, 2017.

	Level 3 Financial Assets and Financial Liabilities For the Three Months Ended March 31, 2017
(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	$	0.2	$	—	$	—	$	—	$	—	$	—	$	0.2
Corporate and municipal bonds	—		—		—		—		—		—		—
	$	0.2	$	—	$	—	$	—	$	—	$	—	$	0.2
(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
Liabilities:
Contingent liabilities	$	0.8	$	—	$	0.1	$	—	$	—	$	—	$	0.9

	Level 3 Financial Assets and Financial Liabilities For the Six Months Ended March 31, 2017
(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	$	0.2	$	—	$	—	$	—	$	—		$	—	$	0.2
Corporate and municipal bonds	3.0		—		—		—		(3.0		)	—		—
	$	3.2	$	—	$	—	$	—	$	(3.0	)	$	—	$	0.2
(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
Liabilities:
Contingent liabilities	$	0.8	$	—	$	0.1	$	—	$	—		$	—	$	0.9

	Level 3 Financial Assets and Financial Liabilities For the Three Months Ended March 31, 2016
(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	$	0.3	$	—	$	—	$	—	$	—		$	—	$	0.3
Corporate and municipal bonds	3.2		—		0.1		—		—			—		3.3
	$	3.5	$	—	$	0.1	$	—	$	—		$	—	$	3.6
(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
Liabilities:
Contingent liabilities	$	3.5	$	—	$	0.1	$	—	$	(2.1	)	$	—	$	1.5