v3.26.3
Earnings Per Share (Computation Of Basic And Diluted Earnings Per Share) (Detail) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Basic and diluted earnings per share:        
Net income (loss) from continuing operations $ (23) $ (7) $ (107) $ (125)
Less: Net income (loss) from continuing operations attributable to noncontrolling interests 1 0 2 0
Net income (loss) from discontinued operations attributable to MBIA Inc. 0 (1) (1) (1)
Net income (loss) attributable to MBIA Inc. available to common shareholders $ (24) $ (8) $ (110) $ (126)
Basic weighted average shares [1] 50,262,358 49,597,200 50,087,036 49,169,475
Diluted weighted average shares [1] 50,262,358 49,597,200 50,087,036 49,169,475
Continuing operations - Basic $ (0.49) $ (0.15) $ (2.19) $ (2.54)
Continuing operations - Diluted (0.49) (0.15) (2.19) (2.54)
Discontinued operations - Basic 0 (0.02) (0.01) (0.03)
Discontinued operations - Diluted 0 (0.02) (0.01) (0.03)
Net income (loss) per share attributable to MBIA Inc. - basic (0.49) (0.17) (2.2) (2.57)
Net income (loss) per share attributable to MBIA Inc. - diluted $ (0.49) $ (0.17) $ (2.2) $ (2.57)
Potentially dilutive securities excluded from the calculation of diluted EPS because of antidilutive affect 800,000 900,000 800,000 900,000
MBIA Inc. [Member]        
Basic and diluted earnings per share:        
Net income (loss) from continuing operations $ (24) $ (7) $ (109) $ (125)
Net income (loss) from discontinued operations attributable to MBIA Inc. $ 0 $ (1) $ (1) $ (1)
[1] Includes approximately 1 million of participating securities that met the service condition and were eligible to receive nonforfeitable dividends or dividend equivalents for the three and nine months ended September 30, 2026 and 2025.