v3.26.1
Business Segments (Summary Of Company's Segment Results) (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Segment Reporting Information [Line Items]          
Revenues $ 24 [1] $ 25 [2] $ 48 [3] $ 47 [4]  
Net gains (losses) on financial instruments at fair value and foreign exchange 3 (2) 3 (17)  
Revenues of consolidated VIEs       7  
Inter-segment revenues 0 [5] 0 [6] 0 [7] 0 [8]  
Total revenues 27 [9] 23 [10] 51 [11] 37 [12]  
Losses and loss adjustment 9 8 6 16  
Compensation and benefits 16 12 26 21  
Interest 48 48 95 98  
Inter-segment service charge 0 0 0 0  
Other segment items (3) [13] 11 [14] 8 [15] 20 [16]  
Total expenses 70 79 135 155  
Income (loss) from continuing operations before income taxes (43) (56) (84) (118)  
Total assets per reportable segment 1,979 2,123 1,979 2,123  
Assets held for sale   11   11  
Total assets 1,979 2,134 1,979 2,134 $ 2,013
Operating Segments [Member] | US Public Finance Insurance [Member]          
Segment Reporting Information [Line Items]          
Revenues 16 [1] 15 [2] 31 [3] 26 [4]  
Net gains (losses) on financial instruments at fair value and foreign exchange 1 1 (1) 1  
Revenues of consolidated VIEs       0  
Inter-segment revenues 5 [5] 7 [6] 11 [7] 13 [8]  
Total revenues 22 [9] 23 [10] 41 [11] 40 [12]  
Losses and loss adjustment 5 6 7 9  
Compensation and benefits 0 0 0 0  
Interest 0 0 0 0  
Inter-segment service charge 7 7 16 17  
Other segment items 2 [13] 3 [14] 6 [15] 7 [16]  
Total expenses 14 16 29 33  
Income (loss) from continuing operations before income taxes 8 7 12 7  
Total assets per reportable segment 1,507 1,544 1,507 1,544  
Operating Segments [Member] | Corporate Operations [Member]          
Segment Reporting Information [Line Items]          
Revenues 5 [1] 5 [2] 10 [3] 11 [4]  
Net gains (losses) on financial instruments at fair value and foreign exchange 7 (3) 8 (8)  
Revenues of consolidated VIEs       0  
Inter-segment revenues 10 [5] 12 [6] 23 [7] 27 [8]  
Total revenues 22 [9] 14 [10] 41 [11] 30 [12]  
Losses and loss adjustment 0 0 0 0  
Compensation and benefits 16 12 26 21  
Interest 16 18 33 36  
Inter-segment service charge 0 0 0 0  
Other segment items 3 [13] 4 [14] 6 [15] 8 [16]  
Total expenses 35 34 65 65  
Income (loss) from continuing operations before income taxes (13) (20) (24) (35)  
Total assets per reportable segment 635 677 635 677  
Operating Segments [Member] | International And Structured Finance Insurance [Member]          
Segment Reporting Information [Line Items]          
Revenues 3 [1] 5 [2] 7 [3] 10 [4]  
Net gains (losses) on financial instruments at fair value and foreign exchange (5) 0 (4) (10)  
Revenues of consolidated VIEs       7  
Inter-segment revenues 3 [5] 1 [6] 4 [7] 3 [8]  
Total revenues 1 [9] 6 [10] 7 [11] 10 [12]  
Losses and loss adjustment 4 2 (1) 7  
Compensation and benefits 0 0 0 0  
Interest 37 36 73 74  
Inter-segment service charge 3 3 6 7  
Other segment items (5) [13] 7 [14] 1 [15] 11 [16]  
Total expenses 39 48 79 99  
Income (loss) from continuing operations before income taxes (38) (42) (72) (89)  
Total assets per reportable segment 656 805 656 805  
Intersegment Elimination [Member]          
Segment Reporting Information [Line Items]          
Revenues 0 [1] 0 [2] 0 [3] 0 [4]  
Net gains (losses) on financial instruments at fair value and foreign exchange 0 0 0 0  
Revenues of consolidated VIEs       0  
Inter-segment revenues (18) [5] (20) [6] (38) [7] (43) [8]  
Total revenues (18) [9] (20) [10] (38) [11] (43) [12]  
Losses and loss adjustment 0 0 0 0  
Compensation and benefits 0 0 0 0  
Interest (5) (6) (11) (12)  
Inter-segment service charge (10) (10) (22) (24)  
Other segment items (3) [13] (3) [14] (5) [15] (6) [16]  
Total expenses (18) (19) (38) (42)  
Income (loss) from continuing operations before income taxes 0 (1) 0 (1)  
Total assets per reportable segment $ (819) [17] $ (903) [18] $ (819) [17] $ (903) [18]  
[1] Consists primarily of net premiums earned, net investment income, net realized investment gains (losses), fees and reimbursements and other net realized gains (losses).
[2] Consists primarily of net premiums earned, net investment income, net realized investment gains (losses), fees and reimbursements and other net realized gains (losses).
[3] Consists primarily of net premiums earned, net investment income, net realized investment gains (losses), fees and reimbursements and other net realized gains (losses).
[4] Consists primarily of net premiums earned, net investment income, net realized investment gains (losses), fees and reimbursements and other net realized gains (losses).
[5] Primarily represents intercompany service charges and intercompany net investment income.
[6] Primarily represents intercompany service charges and intercompany net investment income.
[7] Primarily represents intercompany service charges and intercompany net investment income.
[8] Primarily represents intercompany service charges and intercompany net investment income.
[9] Includes net investment income of $15 million, $5 million, $3 million, and ($6) million for the U.S. Public Finance, Corporate, International and Structured Finance, and Eliminations segments, respectively.
[10] Includes net investment income of $15 million, $6 million, $3 million, and ($5) million for the U.S. Public Finance, Corporate, International and Structured Finance, and Eliminations segments, respectively.
[11] Includes net investment income of $30 million, $11 million, $6 million, and ($12) million for the U.S. Public Finance, Corporate, International and Structured Finance, and Eliminations segments, respectively.
[12] Includes net investment income of $30 million, $13 million, $6 million, and ($12) million for the U.S. Public Finance, Corporate, International and Structured Finance, and Eliminations segments, respectively.
[13] Other segment items for each reportable segment include:

a. U.S. Public Finance Insurance - amortization of deferred acquisition costs ("DAC"), professional service fees, occupancy costs and other operating expenses;

b. Corporate - professional service fees, occupancy costs and other operating expenses;

c. International and Structured Finance Insurance - expenses of consolidated VIEs, amortization of DAC, professional service fees and other operating expenses, and

d. Elimination - inter-segment amortization of DAC and inter-segment occupancy costs.
[14] Other segment items for each reportable segment include:

a. U.S. Public Finance Insurance - amortization of DAC, professional service fees, occupancy costs and other operating expenses;

b. Corporate - professional service fees, occupancy costs and other operating expenses;

c. International and Structured Finance Insurance - expenses of consolidated VIEs, amortization of DAC, professional service fees and other operating expenses, and

d. Elimination - inter-segment amortization of DAC and inter-segment occupancy costs.
[15] Other segment items for each reportable segment include:

a. U.S. Public Finance Insurance - amortization of DAC, professional service fees, occupancy costs and other operating expenses;

b. Corporate - professional service fees, occupancy costs and other operating expenses;

c. International and Structured Finance Insurance - expenses of consolidated VIEs, amortization of DAC, professional service fees and other operating expenses, and

d. Elimination - inter-segment amortization of DAC and inter-segment occupancy costs.
[16] Other segment items for each reportable segment include:

a. U.S. Public Finance Insurance - amortization of DAC, professional service fees, occupancy costs and other operating expenses;

b. Corporate - professional service fees, occupancy costs and other operating expenses;

c. International and Structured Finance Insurance - expenses of consolidated VIEs, amortization of DAC, professional service fees and other operating expenses, and

d. Elimination - inter-segment amortization of DAC and inter-segment occupancy costs.
[17] Consists principally of intercompany reinsurance balances.
[18] Consists principally of intercompany reinsurance balances.