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Regulatory Requirements (Summary Of Capital, Capital Requirements And Excess Capital) (Details) $ in Millions	Dec. 31, 2016 USD ($)
Net Capital / Eligible Equity	$ 4,796
Required net capital	565
Excess regulatory capital	4,231
IB LLC [Member]
Net Capital / Eligible Equity	3,254
Required net capital	294
Excess regulatory capital	2,960
TH LLC [Member]
Net Capital / Eligible Equity	306
Required net capital	1
Excess regulatory capital	305
THE [Member]
Net Capital / Eligible Equity	577
Required net capital	174
Excess regulatory capital	403
Other Regulated Operating Companies [Member]
Net Capital / Eligible Equity	659
Required net capital	96
Excess regulatory capital	$ 563

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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