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Business Segments (Summary Of Company's Segment Results) (Detail) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020 | Dec. 31, 2020
Segment Reporting Information [Line Items] |  |  |  |  |  |
Revenues | [1] | $ 29 | $ 39 | $ 64 | $ 82 |
Net gains (losses) on financial instruments at fair value and foreign exchange |  | (20) | 24 | 31 | (39) |
Net gains (losses) on extinguishment of debt |  | 14 |  | 14 |  |
Revenues of consolidated VIEs |  | (5) | 51 | (19) | 65 |
Inter-segment revenues | [2] | 0 | 0 | 0 | 0 |
Total revenues |  | 18 | 114 | 90 | 108 |
Losses and loss adjustment |  | 9 | 136 | 107 | 379 |
Operating |  | 24 | 25 | 52 | 45 |
Interest |  | 41 | 45 | 82 | 92 |
Expenses of consolidated VIEs |  | 5 | 14 | 16 | 31 |
Inter-segment expenses | [2] | 0 | 0 | 0 | 0 |
Total expenses |  | 79 | 220 | 257 | 547 |
Income (loss) before income taxes |  | (61) | (106) | (167) | (439) |
Identifiable assets |  | 5,252 |  | 5,252 |  | $ 5,751
Operating Segments [Member] | US Public Finance Insurance [Member] |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |
Revenues | [1] | 21 | 26 | 44 | 57 |
Net gains (losses) on financial instruments at fair value and foreign exchange |  | 3 | 25 | 0 | 7 |
Net gains (losses) on extinguishment of debt |  | 0 |  | 0 |  |
Revenues of consolidated VIEs |  | 0 | 0 | 0 | 0 |
Inter-segment revenues | [2] | 6 | 8 | 14 | 14 |
Total revenues |  | 30 | 59 | 58 | 78 |
Losses and loss adjustment |  | (42) | 72 | 67 | 120 |
Operating |  | 4 | 3 | 8 | 5 |
Interest |  | 0 | 0 | 0 | 0 |
Expenses of consolidated VIEs |  | 0 | 0 | 0 | 0 |
Inter-segment expenses | [2] | 11 | 11 | 25 | 25 |
Total expenses |  | (27) | 86 | 100 | 150 |
Income (loss) before income taxes |  | 57 | (27) | (42) | (72) |
Identifiable assets |  | 3,593 |  | 3,593 |  |
Operating Segments [Member] | Corporate Operations [Member] |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |
Revenues | [1] | 2 | 5 | 7 | 11 |
Net gains (losses) on financial instruments at fair value and foreign exchange |  | (18) | 0 | 37 | (56) |
Net gains (losses) on extinguishment of debt |  | 14 |  | 14 |  |
Revenues of consolidated VIEs |  | 0 | 0 | 0 | 0 |
Inter-segment revenues | [2] | 18 | 17 | 36 | 35 |
Total revenues |  | 16 | 22 | 94 | (10) |
Losses and loss adjustment |  | 0 | 0 | 0 | 0 |
Operating |  | 17 | 19 | 38 | 34 |
Interest |  | 14 | 16 | 28 | 32 |
Expenses of consolidated VIEs |  | 0 | 0 | 0 | 0 |
Inter-segment expenses | [2] | 4 | 6 | 10 | 11 |
Total expenses |  | 35 | 41 | 76 | 77 |
Income (loss) before income taxes |  | (19) | (19) | 18 | (87) |
Identifiable assets |  | 852 |  | 852 |  |
Operating Segments [Member] | International And Structured Finance Insurance [Member] |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |
Revenues | [1] | 6 | 8 | 13 | 14 |
Net gains (losses) on financial instruments at fair value and foreign exchange |  | (5) | (1) | (6) | 10 |
Net gains (losses) on extinguishment of debt |  | 0 |  | 0 |  |
Revenues of consolidated VIEs |  | (5) | 51 | (19) | 65 |
Inter-segment revenues | [2] | 4 | 3 | 8 | 8 |
Total revenues |  | 0 | 61 | (4) | 97 |
Losses and loss adjustment |  | 51 | 64 | 40 | 259 |
Operating |  | 3 | 3 | 6 | 6 |
Interest |  | 27 | 29 | 54 | 60 |
Expenses of consolidated VIEs |  | 5 | 14 | 16 | 31 |
Inter-segment expenses | [2] | 11 | 11 | 21 | 21 |
Total expenses |  | 97 | 121 | 137 | 377 |
Income (loss) before income taxes |  | (97) | (60) | (141) | (280) |
Identifiable assets |  | 3,346 |  | 3,346 |  |
Intersegment Elimination [Member] |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |
Revenues | [1] | 0 | 0 | 0 | 0 |
Net gains (losses) on financial instruments at fair value and foreign exchange |  | 0 | 0 | 0 | 0 |
Net gains (losses) on extinguishment of debt |  | 0 |  | 0 |  |
Revenues of consolidated VIEs |  | 0 | 0 | 0 | 0 |
Inter-segment revenues | [2] | (28) | (28) | (58) | (57) |
Total revenues |  | (28) | (28) | (58) | (57) |
Losses and loss adjustment |  | 0 | 0 | 0 | 0 |
Operating |  | 0 | 0 | 0 | 0 |
Interest |  | 0 | 0 | 0 | 0 |
Expenses of consolidated VIEs |  | 0 | 0 | 0 | 0 |
Inter-segment expenses | [2] | (26) | (28) | (56) | (57) |
Total expenses |  | (26) | (28) | (56) | (57) |
Income (loss) before income taxes |  | (2) | $ 0 | (2) | $ 0 |
Identifiable assets | [3] | $ (2,539) |  | $ (2,539) |  |
[1] | Represents the sum of third-party financial guarantee net premiums earned, net investment income, insurance-related fees and reimbursements and other fees.
[2] | Represents intercompany premium income and expense and intercompany interest income and expense pertaining to intercompany receivables and payables.
[3] | Consists principally of intercompany reinsurance balances.

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