Financial Guaranty Insurance Losses - BIG Transaction Loss Summary (Details) $ in Millions		6 Months Ended	12 Months Ended
		Jun. 30, 2015 USD ($) risk	Dec. 31, 2014 USD ($) risk
Discount
Total		$ (494)
Reserves (salvage)
Total		$ 779	$ 567
BIG [Member]
Number of risks
Total (in contracts) | risk	[1]	468	358
Remaining weighted average contract period
Total (in years)		10 years 1 month 6 days	10 years 3 months 18 days
Principal
Total		$ 16,904	$ 15,222
Interest
Total		8,362	7,651
Total net outstanding exposure
Total	[2]	25,266	22,873
Expected cash outflows (inflows)
Total		2,737	3,118
Potential recoveries
Total, Undiscounted R&W		(144)	(239)
Total, Other	[3]	(835)	(1,477)
Total		(979)	(1,716)
Subtotal
Total		1,758	1,402
Discount
Total		(494)	(413)
Present value of expected cash flows
Net expected loss to be paid		1,264	989
Deferred premium revenue
Total		882	584
Reserves (salvage)
Total	[4]	$ 760	$ 571
BIG [Member] | Consolidated Entity Excluding Consolidation of Variable Interest Entities (VIE) [Member]
Number of risks
Total (in contracts) | risk	[1]	468	358
Remaining weighted average contract period
Total (in years)		10 years 1 month 6 days	10 years 3 months 18 days
Principal
Total		$ 16,904	$ 15,222
Interest
Total		8,362	7,651
Total net outstanding exposure
Total	[2]	25,266	22,873
Expected cash outflows (inflows)
Total		3,076	3,463
Potential recoveries
Total, Undiscounted R&W		(153)	(247)
Total, Other	[3]	(1,015)	(1,654)
Total		(1,168)	(1,901)
Subtotal
Total		1,908	1,562
Discount
Total		(530)	(447)
Present value of expected cash flows
Net expected loss to be paid		1,378	1,115
Deferred premium revenue
Total		989	700
Reserves (salvage)
Total	[4]	$ 829	$ 650
BIG [Member] | Consolidated Entity Excluding Consolidation of Variable Interest Entities (VIE) [Member] | BIG 1 [Member]
Number of risks
Ceded (in contracts) | risk	[1]	(54)	(59)
Total (in contracts) | risk	[1]	266	164
Remaining weighted average contract period
Gross (in years)		9 years 8 months 12 days	9 years 10 months 24 days
Ceded (in years)		6 years 6 months	7 years 4 months 24 days
Principal
Gross		$ 12,125	$ 12,358
Ceded		(1,621)	(2,163)
Interest
Gross		6,019	6,350
Ceded		(542)	(838)
Total net outstanding exposure
Gross	[2]	18,144	18,708
Ceded	[2]	(2,163)	(3,001)
Expected cash outflows (inflows)
Gross		561	1,762
Ceded		(28)	(626)
Total		142	39
Potential recoveries
Gross, Undiscounted R&W		17	(39)
Ceded, Undiscounted R&W		(1)	0
Gross, Other	[3]	(446)	(1,687)
Ceded, Other	[3]	14	608
Ceded		13	608
Gross		(429)	(1,726)
Subtotal
Gross		132	36
Ceded		(15)	(18)
Discount
Gross		10	3
Ceded		(1)	0
Present value of expected cash flows
Ceded		(16)	(18)
Deferred premium revenue
Gross		631	378
Ceded		(59)	(70)
Reserves (salvage)
Gross	[4]	7	(42)
Ceded	[4]	$ (8)	$ (5)
BIG [Member] | Consolidated Entity Excluding Consolidation of Variable Interest Entities (VIE) [Member] | BIG 2 [Member]
Number of risks
Ceded (in contracts) | risk	[1]	(14)	(15)
Total (in contracts) | risk	[1]	76	75
Remaining weighted average contract period
Gross (in years)		10 years 3 months 18 days	10 years 1 month 6 days
Ceded (in years)		8 years 1 month 6 days	8 years 10 months 24 days
Principal
Gross		$ 3,696	$ 2,421
Ceded		(307)	(286)
Interest
Gross		2,005	1,274
Ceded		(122)	(121)
Total net outstanding exposure
Gross	[2]	5,701	3,695
Ceded	[2]	(429)	(407)
Expected cash outflows (inflows)
Gross		1,012	763
Ceded		(79)	(77)
Total		564	392
Potential recoveries
Gross, Undiscounted R&W		(49)	(48)
Ceded, Undiscounted R&W		1	2
Gross, Other	[3]	(209)	(206)
Ceded, Other	[3]	6	5
Ceded		7	7
Gross		(258)	(254)
Subtotal
Gross		754	509
Ceded		(72)	(70)
Discount
Gross		(190)	(117)
Ceded		13	11
Present value of expected cash flows
Ceded		(59)	(59)
Deferred premium revenue
Gross		144	119
Ceded		(4)	(6)
Reserves (salvage)
Gross	[4]	459	278
Ceded	[4]	$ (54)	$ (53)
BIG [Member] | Consolidated Entity Excluding Consolidation of Variable Interest Entities (VIE) [Member] | BIG 3 [Member]
Number of risks
Ceded (in contracts) | risk	[1]	(41)	(38)
Total (in contracts) | risk	[1]	126	119
Remaining weighted average contract period
Gross (in years)		9 years 2 months 12 days	9 years 7 months 6 days
Ceded (in years)		6 years 8 months 12 days	6 years 10 months 24 days
Principal
Gross		$ 3,147	$ 3,067
Ceded		(136)	(175)
Interest
Gross		1,039	1,034
Ceded		(37)	(48)
Total net outstanding exposure
Gross	[2]	4,186	4,101
Ceded	[2]	(173)	(223)
Expected cash outflows (inflows)
Gross		1,659	1,716
Ceded		(49)	(75)
Total		768	788
Potential recoveries
Gross, Undiscounted R&W		(127)	(171)
Ceded, Undiscounted R&W		6	9
Gross, Other	[3]	(399)	(404)
Ceded, Other	[3]	19	30
Ceded		25	39
Gross		(526)	(575)
Subtotal
Gross		1,133	1,141
Ceded		(24)	(36)
Discount
Gross		(365)	(353)
Ceded		3	9
Present value of expected cash flows
Ceded		(21)	(27)
Deferred premium revenue
Gross		296	312
Ceded		(19)	(33)
Reserves (salvage)
Gross	[4]	433	482
Ceded	[4]	(8)	(10)
BIG [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Expected cash outflows (inflows)
Total		(339)	(345)
Potential recoveries
Total, Undiscounted R&W		9	8
Total, Other	[3]	180	177
Total		189	185
Subtotal
Total		(150)	(160)
Discount
Total		36	34
Present value of expected cash flows
Net expected loss to be paid		(114)	(126)
Deferred premium revenue
Total		(107)	(116)
Reserves (salvage)
Total	[4]	$ (69)	$ (79)

[1] A risk represents the aggregate of the financial guaranty policies that share the same revenue source for purposes of making Debt Service payments. The ceded number of risks represents the number of risks for which the Company ceded a portion of its exposure

[2] Includes BIG amounts related to FG VIEs.

[3] Includes excess spread and draws on HELOCs.

[4] See table “Components of net reserves (salvage).”