Outstanding Exposure - Amortization Schedule of Puerto Rico BIG Net Par Outstanding and BIG Net Debt Service Outstanding (Details) - USD ($) $ in Millions	Dec. 31, 2015		Dec. 31, 2014
Estimated BIG Net Par Amortization [Abstract]
Net Par Outstanding	$ 358,571	[1],[2]	$ 403,729	[3]
Estimated BIG Net Debt Service Amortization [Abstract]
Total	536,341		609,622
Puerto Rico [Member]
Estimated BIG Net Par Amortization [Abstract]
2016	302
2017	222
2018	179
2019	204
2020	270
2021	125
2022	115
2023	151
2024	174
2025	196
2026-2030	942
2031-2035	1,131
2036-2040	571
2041-2045	303
2046-2047	168
Net Par Outstanding	5,053	[4]	4,939
Estimated BIG Net Debt Service Amortization [Abstract]
2016	559
2017	464
2018	410
2019	424
2020	482
2021	323
2022	305
2023	337
2024	352
2025	363
2026-2030	1,632
2031-2035	1,601
2036-2040	775
2041-2045	389
2046-2047	181
Total	8,597
BIG [Member]
Estimated BIG Net Par Amortization [Abstract]
Net Par Outstanding	15,183		18,247
Subject to the Terms of the Recovery Act [Member] | Puerto Rico [Member]
Estimated BIG Net Par Amortization [Abstract]
2016	98
2017	51
2018	56
2019	74
2020	87
2021	66
2022	47
2023	110
2024	89
2025	111
2026-2030	590
2031-2035	583
2036-2040	308
2041-2045	137
2046-2047	168
Net Par Outstanding	2,575	[4]	2,447
Estimated BIG Net Debt Service Amortization [Abstract]
2016	229
2017	175
2018	178
2019	192
2020	202
2021	177
2022	153
2023	214
2024	188
2025	206
2026-2030	973
2031-2035	838
2036-2040	427
2041-2045	207
2046-2047	181
Total	4,540
Not Subject to the Terms of the Recovery Act [Member] | Puerto Rico [Member]
Estimated BIG Net Par Amortization [Abstract]
2016	204
2017	171
2018	123
2019	130
2020	183
2021	59
2022	68
2023	41
2024	85
2025	85
2026-2030	352
2031-2035	548
2036-2040	263
2041-2045	166
2046-2047	0
Net Par Outstanding	2,478	[4]	$ 2,492
Estimated BIG Net Debt Service Amortization [Abstract]
2016	330
2017	289
2018	232
2019	232
2020	280
2021	146
2022	152
2023	123
2024	164
2025	157
2026-2030	659
2031-2035	763
2036-2040	348
2041-2045	182
2046-2047	0
Total	$ 4,057

[1] Excludes $1.5 billion of loss mitigation securities insured and held by the Company as of December 31, 2015, which are primarily BIG.

[2] The December 31, 2015 amounts include $10.9 billion of net par acquired from Radian Asset.

[3] Excludes $1.3 billion of loss mitigation securities insured and held by the Company as of December 31, 2014, which are primarily BIG.

[4] As of December 31, 2015, the Company's Puerto Rico net exposures increased due to (1) net par of $385 million acquired in the Radian Asset Acquisition, of which $21 million was of PREPA and $166 million of PRHTA, and (2) a commutation of previously ceded Puerto Rico exposures.