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Consolidated Statement Of Changes In Shareholders' Equity - USD ($) $ in Millions | Total | Preferred Stock [Member] | Total Shareholders' Equity Of MBIA Inc. [Member] | Common Stock [Member] | Additional Paid-in Capital [Member] | Retained Earnings [Member] | Accumulated Other Comprehensive Income (Loss) [Member] | Treasury Stock [Member]
--- | --- | --- | --- | --- | --- | --- | --- | ---
Total equity balance at Dec. 31, 2017 |  |  | $ 1,413 |  | $ 3,171 | $ 1,095 | $ (19) | $ (3,118)
Balance (in common stock shares) at Dec. 31, 2017 |  |  |  | 283,717,973 |  |  |  |
Balance (in treasury stock shares) at Dec. 31, 2017 |  |  |  |  |  |  |  | (192,233,526)
Cumulative effect of prospective application of new accounting principle | ASU 2016-01 [Member] |  |  |  |  |  | 164 | (164) |
Cumulative effect of prospective application of new accounting principle | ASU 2018-02 [Member] |  |  |  |  |  | 3 | (3) |
Net income (loss) | $ (244) |  |  |  |  | (244) |  |
Total other comprehensive income (loss) | (69) |  |  |  |  |  | (69) |
Treasury shares issued |  |  |  |  | (21) |  |  | $ 34
Treasury shares issued (in shares) |  |  |  |  |  |  |  | 1,277,620
Treasury shares acquired |  |  |  |  |  |  |  | $ (14)
Treasury shares acquired (in shares) |  |  |  |  |  |  |  | (1,961,711)
Share-based compensation, net of tax |  |  |  |  | 4 |  |  | $ 0
Share-based compensation (in shares) |  |  |  | (92,284) |  |  |  | (46,081)
Period change |  |  | (310) |  |  |  |  |
Total equity balance at Jun. 30, 2018 | 1,115 | $ 12 | 1,103 | $ 284 | 3,154 | 1,018 | (255) | $ (3,098)
Balance (in common stock shares) at Jun. 30, 2018 |  |  |  | 283,625,689 |  |  |  |
Balance (in treasury stock shares) at Jun. 30, 2018 |  |  |  |  |  |  |  | (192,963,698)
Balance (in preferred stock shares) at Jun. 30, 2018 |  | 1,315 |  |  |  |  |  |
Total equity balance at Mar. 31, 2018 |  |  | 1,248 |  | 3,174 | 1,164 | (241) | $ (3,133)
Balance (in common stock shares) at Mar. 31, 2018 |  |  |  | 283,569,254 |  |  |  |
Balance (in treasury stock shares) at Mar. 31, 2018 |  |  |  |  |  |  |  | (194,243,689)
Cumulative effect of prospective application of new accounting principle | ASU 2016-01 [Member] |  |  |  |  |  | 0 | 0 |
Cumulative effect of prospective application of new accounting principle | ASU 2018-02 [Member] |  |  |  |  |  | 0 | 0 |
Net income (loss) | (146) |  |  |  |  | (146) |  |
Total other comprehensive income (loss) | (14) |  |  |  |  |  | (14) |
Treasury shares issued |  |  |  |  | (21) |  |  | $ 34
Treasury shares issued (in shares) |  |  |  |  |  |  |  | 1,277,620
Treasury shares acquired |  |  |  |  |  |  |  | $ 0
Treasury shares acquired (in shares) |  |  |  |  |  |  |  | 0
Share-based compensation, net of tax |  |  |  |  | 1 |  |  | $ 1
Share-based compensation (in shares) |  |  |  | 56,435 |  |  |  | 2,371
Period change |  |  | (145) |  |  |  |  |
Total equity balance at Jun. 30, 2018 | 1,115 | $ 12 | 1,103 | $ 284 | 3,154 | 1,018 | (255) | $ (3,098)
Balance (in common stock shares) at Jun. 30, 2018 |  |  |  | 283,625,689 |  |  |  |
Balance (in treasury stock shares) at Jun. 30, 2018 |  |  |  |  |  |  |  | (192,963,698)
Balance (in preferred stock shares) at Jun. 30, 2018 |  | 1,315 |  |  |  |  |  |
Total equity balance at Dec. 31, 2018 | $ 1,132 |  | 1,119 |  | 3,025 | 966 | (156) | $ (3,000)
Balance (in common stock shares) at Dec. 31, 2018 | 283,625,689 |  |  | 283,625,689 |  |  |  |
Balance (in treasury stock shares) at Dec. 31, 2018 | (193,803,976) |  |  |  |  |  |  | (193,803,976)
Cumulative effect of prospective application of new accounting principle | ASU 2016-01 [Member] |  |  |  |  |  | 0 | 0 |
Cumulative effect of prospective application of new accounting principle | ASU 2018-02 [Member] |  |  |  |  |  | 0 | 0 |
Net income (loss) | $ (187) |  |  |  |  | (187) |  |
Total other comprehensive income (loss) | 152 |  |  |  |  |  | 152 |
Treasury shares issued |  |  |  |  | 0 |  |  |
Treasury shares issued (in shares) |  |  |  |  |  |  |  | 0
Treasury shares acquired |  |  |  |  |  |  |  | $ (54)
Treasury shares acquired (in shares) |  |  |  |  |  |  |  | (5,932,659)
Share-based compensation, net of tax |  |  |  |  | (30) |  |  | $ 40
Share-based compensation (in shares) |  |  |  | 0 |  |  |  | 911,942
Period change |  |  | (79) |  |  |  |  |
Total equity balance at Jun. 30, 2019 | $ 1,053 | $ 13 | 1,040 | $ 284 | 2,995 | 779 | (4) | $ (3,014)
Balance (in common stock shares) at Jun. 30, 2019 | 283,625,689 |  |  | 283,625,689 |  |  |  |
Balance (in treasury stock shares) at Jun. 30, 2019 | (198,824,693) |  |  |  |  |  |  | (198,824,693)
Balance (in preferred stock shares) at Jun. 30, 2019 | 0 | 1,315 |  |  |  |  |  |
Total equity balance at Mar. 31, 2019 |  |  | 1,188 |  | 2,996 | 949 | (74) | $ (2,967)
Balance (in common stock shares) at Mar. 31, 2019 |  |  |  | 283,625,689 |  |  |  |
Balance (in treasury stock shares) at Mar. 31, 2019 |  |  |  |  |  |  |  | (193,446,168)
Cumulative effect of prospective application of new accounting principle | ASU 2016-01 [Member] |  |  |  |  |  | 0 | 0 |
Cumulative effect of prospective application of new accounting principle | ASU 2018-02 [Member] |  |  |  |  |  | 0 | 0 |
Net income (loss) | $ (170) |  |  |  |  | (170) |  |
Total other comprehensive income (loss) | 70 |  |  |  |  |  | 70 |
Treasury shares issued |  |  |  |  | 0 |  |  |
Treasury shares issued (in shares) |  |  |  |  |  |  |  | 0
Treasury shares acquired |  |  |  |  |  |  |  | $ (50)
Treasury shares acquired (in shares) |  |  |  |  |  |  |  | (5,445,053)
Share-based compensation, net of tax |  |  |  |  | (1) |  |  | $ 3
Share-based compensation (in shares) |  |  |  | 0 |  |  |  | 66,528
Period change |  |  | (148) |  |  |  |  |
Total equity balance at Jun. 30, 2019 | $ 1,053 | $ 13 | $ 1,040 | $ 284 | $ 2,995 | $ 779 | $ (4) | $ (3,014)
Balance (in common stock shares) at Jun. 30, 2019 | 283,625,689 |  |  | 283,625,689 |  |  |  |
Balance (in treasury stock shares) at Jun. 30, 2019 | (198,824,693) |  |  |  |  |  |  | (198,824,693)
Balance (in preferred stock shares) at Jun. 30, 2019 | 0 | 1,315 |  |  |  |  |  |

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