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Business Segments (Summary Of Company's Segment Results) (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Segment Reporting Information [Line Items] |  |  |  |
Revenues | [1] | $ 148 | $ 199 | $ 330
Net change in fair value of insured derivatives |  |  | 6 | 15
Net gains (losses) on financial instruments at fair value and foreign exchange |  | 40 | (86) | (78)
Net investment losses related to other-than-temporary impairments |  |  |  | (67)
Net gains (losses) on extinguishment of debt |  | 30 |  | (1)
Other net realized gains (losses) |  | (6) | 0 | 4
Revenues of consolidated VIEs |  | (23) | 163 | 77
Inter-segment revenues | [2] | 0 | 0 | 0
Total revenues |  | 189 | 282 | 280
Losses and loss adjustment |  | 350 | 530 | 242
Amortization of deferred acquisition costs and operating |  | 97 | 97 | 103
Interest |  | 163 | 178 | 201
Expenses of consolidated VIEs |  | 24 | 55 | 91
Inter-segment expenses | [2] | 0 | 0 | 0
Total expenses |  | 634 | 860 | 637
Income (loss) before income taxes |  | (445) | (578) | (357)
Identifiable assets |  | 4,696 | 5,751 |
Operating Segments [Member] | US Public Finance Insurance [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | [1] | 85 | 139 | 263
Net change in fair value of insured derivatives |  |  | 0 | 0
Net gains (losses) on financial instruments at fair value and foreign exchange |  | (2) | 2 | 15
Net investment losses related to other-than-temporary impairments |  |  |  | (67)
Net gains (losses) on extinguishment of debt |  | 0 |  | 0
Other net realized gains (losses) |  | 0 | (1) | 2
Revenues of consolidated VIEs |  | 0 | 0 | 21
Inter-segment revenues | [2] | 27 | 28 | 28
Total revenues |  | 110 | 168 | 262
Losses and loss adjustment |  | 227 | 163 | 53
Amortization of deferred acquisition costs and operating |  | 17 | 14 | 13
Interest |  | 0 | 0 | 0
Expenses of consolidated VIEs |  | 0 | 0 | 0
Inter-segment expenses | [2] | 45 | 45 | 52
Total expenses |  | 289 | 222 | 118
Income (loss) before income taxes |  | (179) | (54) | 144
Identifiable assets |  | 3,313 | 3,644 |
Operating Segments [Member] | Corporate Operations [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | [1] | 20 | 31 | 32
Net change in fair value of insured derivatives |  |  | 0 | 0
Net gains (losses) on financial instruments at fair value and foreign exchange |  | 56 | (74) | (59)
Net investment losses related to other-than-temporary impairments |  |  |  | 0
Net gains (losses) on extinguishment of debt |  | 30 |  | (1)
Other net realized gains (losses) |  | (7) | 0 | (2)
Revenues of consolidated VIEs |  | 0 | 0 | 1
Inter-segment revenues | [2] | 67 | 66 | 62
Total revenues |  | 166 | 23 | 33
Losses and loss adjustment |  | 0 | 0 | 0
Amortization of deferred acquisition costs and operating |  | 71 | 69 | 69
Interest |  | 56 | 65 | 73
Expenses of consolidated VIEs |  | 0 | 0 | 0
Inter-segment expenses | [2] | 22 | 22 | 23
Total expenses |  | 149 | 156 | 165
Income (loss) before income taxes |  | 17 | (133) | (132)
Identifiable assets |  | 873 | 954 |
Operating Segments [Member] | International And Structured Finance Insurance [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | [1] | 43 | 29 | 35
Net change in fair value of insured derivatives |  |  | 6 | 15
Net gains (losses) on financial instruments at fair value and foreign exchange |  | (14) | (14) | (34)
Net investment losses related to other-than-temporary impairments |  |  |  | 0
Net gains (losses) on extinguishment of debt |  | 0 |  | 0
Other net realized gains (losses) |  | 1 | 1 | 4
Revenues of consolidated VIEs |  | (23) | 163 | 55
Inter-segment revenues | [2] | 12 | 12 | 21
Total revenues |  | 19 | 197 | 96
Losses and loss adjustment |  | 123 | 367 | 189
Amortization of deferred acquisition costs and operating |  | 9 | 14 | 21
Interest |  | 107 | 113 | 128
Expenses of consolidated VIEs |  | 24 | 55 | 91
Inter-segment expenses | [2] | 38 | 39 | 36
Total expenses |  | 301 | 588 | 465
Income (loss) before income taxes |  | (282) | (391) | (369)
Identifiable assets |  | 2,800 | 3,671 |
Intersegment Elimination [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | [1] | 0 | 0 | 0
Net change in fair value of insured derivatives |  |  | 0 | 0
Net gains (losses) on financial instruments at fair value and foreign exchange |  | 0 | 0 | 0
Net investment losses related to other-than-temporary impairments |  |  |  | 0
Net gains (losses) on extinguishment of debt |  | 0 |  | 0
Other net realized gains (losses) |  | 0 | 0 | 0
Revenues of consolidated VIEs |  | 0 | 0 | 0
Inter-segment revenues | [2] | (106) | (106) | (111)
Total revenues |  | (106) | (106) | (111)
Losses and loss adjustment |  | 0 | 0 | 0
Amortization of deferred acquisition costs and operating |  | 0 | 0 | 0
Interest |  | 0 | 0 | 0
Expenses of consolidated VIEs |  | 0 | 0 | 0
Inter-segment expenses | [2] | (105) | (106) | (111)
Total expenses |  | (105) | (106) | (111)
Income (loss) before income taxes |  | (1) | 0 | $ 0
Identifiable assets | [3] | $ (2,290) | $ (2,518) |
[1] | Consists of net premiums earned, net investment income, net realized investment gains (losses), insurance-related fees and reimbursements and other fees.
[2] | Primarily represents intercompany service charges and intercompany net investment income and expense.
[3] | Consists principally of intercompany reinsurance balances.

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