v3.4.0.3

Income Taxes (Narrative) (Details) - USD ($) $ in Billions	Mar. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
Undistributed accumulated earnings of foreign subsidiaries	$ 1.0	$ 1.0
Accumulated earnings of foreign pass through subsidiaries	0.4	0.4
Accumulated earnings subject to additional foreign tax	$ 0.2	$ 0.3

X

- Definition

Accumulated earnings attributable to our foreign subsidiaries that are considered pass-through entities for U.S. income tax purposes.

+ References

No definition available.

+ Details

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X

- Definition

Accumulated earnings of certain pass through subsidiaries where repatriation would result in additional foreign taxes in the form of dividend withholding tax imposed on the recipient of the distribution or dividend distribution tax imposed on the payor of the distribution.

+ References

No definition available.

+ Details

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Namespace Prefix:	ibkr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Amount of undistributed earnings of foreign subsidiaries.

+ References

No definition available.

+ Details

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Namespace Prefix:	ibkr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- References

No definition available.

+ Details

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