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Regulatory Requirements (Tables) | 12 Months Ended
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Dec. 31, 2017
Regulatory Requirements [Abstract] |
Summary Of Capital, Capital Requirements And Excess Capital |
﻿ |  |  |  |  |  |  |  |  |
﻿ |  |  |  |  |  |  |  |  |
﻿ |  | Net Capital/ |  |  |  |  |  |
﻿ |  | Eligible Equity |  | Requirement |  | Excess
﻿ |  |  |  |  |  |  |  |  |
﻿ |  | (in millions)
﻿IB LLC |  | $ | 3,548 |  | $ | 495 |  | $ | 3,053
﻿TH LLC |  |  | 279 |  |  | 1 |  |  | 278
﻿THE |  |  | 614 |  |  | 92 |  |  | 522
﻿Other regulated operating companies |  |  | 773 |  |  | 121 |  |  | 652
﻿ |  | $ | 5,214 |  | $ | 709 |  | $ | 4,505
﻿

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