XML 51 R40.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Financial Assets And Financial Liabilities (Trading Gains from Market Making Transactions) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2016 | Jun. 30, 2015 | Jun. 30, 2016 | Jun. 30, 2015
Financial Assets And Financial Liabilities [Abstract] |  |  |  |
Equities | $ 35 | $ 70 | $ 85 | $ 121
Foreign Exchange | (1) | (3) | 1 | 8
Trading gains | $ 34 | $ 67 | $ 86 | $ 129

X
- Definition Trading Gains from Equities + References No definition available. + Details
Name: | ibkr_TradingGainsLossesPLEquities
Namespace Prefix: | ibkr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Trading Gains Foreign Exchange + References No definition available. + Details
Name: | ibkr_TradingGainsLossesPLForeignExchange
Namespace Prefix: | ibkr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_FairValueDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of gain (loss) resulting from the difference between the acquisition price and the selling price or fair value of trading assets and trading liabilities, conducted separately from customer trading activities. Includes, but is not limited to, changes in fair value of trading assets and trading liabilities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.13(e)) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 940 -SubTopic 320 -Section 35 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=35711043&loc=d3e42454-110968 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 940 -SubTopic 320 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=35711157&loc=d3e42567-110969 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4F -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624186-113959 + Details
Name: | us-gaap_TradingGainsLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration