Collateralized Transactions - Collateral Pledged (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	$ 2,843,911	$ 2,819,132
Repurchase Agreements	19,829,249	17,012,332
Total	22,673,160	19,831,464
Corporate equity securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	2,353,798	2,046,243
Repurchase Agreements	214,413	66,291
Total	2,568,211	2,112,534
Corporate debt securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	470,908	731,276
Repurchase Agreements	2,336,702	1,907,888
Total	2,807,610	2,639,164
Mortgage- and asset-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	0	0
Repurchase Agreements	2,562,268	2,171,480
Total	2,562,268	2,171,480
U.S. government and federal agency securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	19,205	41,613
Repurchase Agreements	11,792,534	9,232,624
Total	11,811,739	9,274,237
Municipal securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	0	0
Repurchase Agreements	444,861	553,010
Total	444,861	553,010
Sovereign securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	0	0
Repurchase Agreements	2,023,530	2,625,079
Total	2,023,530	2,625,079
Loans and other receivables
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	0	0
Repurchase Agreements	454,941	455,960
Total	$ 454,941	$ 455,960

Amount, before effects of master netting arrangements, of funds outstanding borrowed in the form of a financial asset repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same financial asset at a date certain for a specified price. Includes repurchase-to-maturity transactions and liabilities not subject to a master netting arrangement.

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- Definition

Amount, before effects of master netting arrangements, of financial assets loaned to entities in exchange for collateral and funds outstanding borrowed in the form of a financial asset repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same financial assets at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 7
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64858031&loc=SL34722452-111729

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 7
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=64858031&loc=SL34722452-111729

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- Definition

Amount, before effects of master netting arrangements, of financial assets loaned to entities in exchange for collateral. Includes liabilities not subject to a master netting arrangement and financial assets transferred other than securities that qualify as secured borrowings.

+ References

+ Details

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- Definition

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+ References

No definition available.

+ Details

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