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Regulatory Requirements (Summary Of Capital, Capital Requirements And Excess Capital) (Details) $ in Millions	Sep. 30, 2016 USD ($)
Net Capital / Eligible Equity	$ 4,817
Required net capital	586
Excess regulatory capital	4,231
IB LLC [Member]
Net Capital / Eligible Equity	3,217
Required net capital	325
Excess regulatory capital	2,892
TH LLC [Member]
Net Capital / Eligible Equity	318
Required net capital	1
Excess regulatory capital	317
THE [Member]
Net Capital / Eligible Equity	603
Required net capital	181
Excess regulatory capital	422
Other Regulated Operating Companies [Member]
Net Capital / Eligible Equity	679
Required net capital	79
Excess regulatory capital	$ 600

X

- Definition

Eligible equity is equal to the sum of audited capital and reserves and the eligible portion of subordinated debt. Net capital is equal to the net worth of the broker dealer, less certain items such as exchange memberships, carrying value of securities not readily marketable, haircuts on marketable securities in proprietary accounts, furniture and equipment and other illiquid assets as defined.

+ References

No definition available.

+ Details

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X

- Definition

The amount by which the company's Total Capital exceeds the minimum required for capital adequacy purposes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826

+ Details

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X

- Definition

Minimum amount of net capital required to be maintained by the entity to engage in securities transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

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- Details

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- Details

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- Details

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