Consolidated Statements Of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Premiums, fees and reimbursements received	$ 32	$ 51
Investment income received	127	182
Insured derivative commutations and losses paid	(34)	(18)
Financial guarantee losses and loss adjustment expenses paid	(497)	(67)
Proceeds from recoveries and reinsurance	91	63
Operating and employee related expenses paid	(77)	(75)
Interest paid, net of interest converted to principal	(82)	(71)
Net cash provided (used) by operating activities	(440)	65
Cash flows from investing activities:
Purchases of available-for-sale investments	(738)	(1,129)
Sales of available-for-sale investments	987	937
Paydowns and maturities of available-for-sale investments	277	256
Purchases of investments at fair value	(118)	(49)
Sales, paydowns and maturities of investments at fair value	138	148
Sales, paydowns and maturities (purchases) of short-term investments, net	(177)	223
Sales, paydowns and maturities of held-to-maturity investments	0	1,799
Paydowns and maturities of loans receivable	137	121
Consolidation of variable interest entities	18	1
Deconsolidation of variable interest entities	0	0
(Payments) proceeds for derivative settlements	(48)	(28)
Collateral (to) from swap counterparty	4	(21)
Other investing	(23)	(4)
Net cash provided (used) by investing activities	457	2,254
Cash flows from financing activities:
Proceeds from investment agreements	4	9
Principal paydowns of investment agreements	(41)	(47)
Principal paydowns of medium-term notes	(67)	(52)
Proceeds from the MBIA Corp. Financing Facility	328	0
Principal paydowns of variable interest entity notes	(183)	(2,034)
Purchases of treasury stock	(79)	(109)
Other financing	(2)	0
Net cash provided (used) by financing activities	(40)	(2,233)
Effect of exchange rate changes on cash and cash equivalents	0	(3)
Net increase (decrease) in cash and cash equivalents	(23)	83
Cash and cash equivalents - beginning of year	187	522
Cash and cash equivalents - end of year	164	605
Reconciliation of net income (loss) to net cash provided (used) by operating activities: [Abstract]
Net income (loss)	(1,301)	(105)
Change in: [Abstract]
Premiums receivable	27	121
Deferred acquisition costs	14	21
Unearned premium revenue	(97)	(194)
Loss and loss adjustment expense reserves	512	30
Insurance loss recoverable	(653)	65
Accrued interest payable	64	54
Accrued expenses	(19)	(13)
Unrealized (gains) losses on insured derivatives	16	20
Net (gains) losses on financial instruments at fair value and foreign exchange	63	63
Other net realized (gains) losses	(65)	1
Deferred income tax provision (benefit)	970	(52)
Interest on variable interest entities, net	19	34
Other operating	10	20
Total adjustments to net income (loss)	861	170
Net cash provided (used) by operating activities	(440)	65
Supplementary Disclosure of Consolidated Cash Flow Information
Non-cash consideration received from the sale of MBIA UK Insurance Limited	$ 332	$ 0