Outstanding Exposure - Amortization Schedule of Puerto Rico BIG Net Par Outstanding and BIG Net Debt Service Outstanding (Details) - USD ($) $ in Millions	Jun. 30, 2015		Dec. 31, 2014
Estimated BIG Net Par Amortization [Abstract]
Net Par Outstanding (excluding loss mitigation bonds)	$ 390,384	[1],[2]	$ 403,729	[3]
Estimated BIG Net Debt Service Amortization [Abstract]
Total	584,428		609,622
Puerto Rico [Member]
Estimated BIG Net Par Amortization [Abstract]
2015 (July 1 - September 30)	338
2015 (October 1 - December 31)	33
2016	302
2017	222
2018	179
2019	204
2020	270
2021	126
2022	115
2023	151
2024	174
2025-2029	1,014
2030-2034	980
2035-2039	712
2040-2044	364
2045-2047	246
Net Par Outstanding (excluding loss mitigation bonds)	5,430	[4],[5]	4,939
Estimated BIG Net Debt Service Amortization [Abstract]
2015 (July 1 - September 30)	474
2015 (October 1 - December 31)	37
2016	561
2017	464
2018	410
2019	424
2020	482
2021	324
2022	305
2023	337
2024	352
2025-2029	1,755
2030-2034	1,499
2035-2039	949
2040-2044	467
2045-2047	272
Total	9,112
BIG [Member]
Estimated BIG Net Par Amortization [Abstract]
Net Par Outstanding (excluding loss mitigation bonds)	20,404	[2]	18,247
Subject to the Terms of the Recovery Act [Member] | Puerto Rico [Member]
Estimated BIG Net Par Amortization [Abstract]
2015 (July 1 - September 30)	131
2015 (October 1 - December 31)	0
2016	98
2017	51
2018	56
2019	74
2020	87
2021	66
2022	47
2023	110
2024	89
2025-2029	619
2030-2034	505
2035-2039	429
2040-2044	97
2045-2047	246
Net Par Outstanding (excluding loss mitigation bonds)	2,705	[4],[5]	2,447
Estimated BIG Net Debt Service Amortization [Abstract]
2015 (July 1 - September 30)	198
2015 (October 1 - December 31)	2
2016	229
2017	175
2018	178
2019	192
2020	202
2021	177
2022	153
2023	214
2024	187
2025-2029	1,032
2030-2034	787
2035-2039	567
2040-2044	171
2045-2047	272
Total	4,736
Not Subject to the Terms of the Recovery Act [Member] | Puerto Rico [Member]
Estimated BIG Net Par Amortization [Abstract]
2015 (July 1 - September 30)	207
2015 (October 1 - December 31)	33
2016	204
2017	171
2018	123
2019	130
2020	183
2021	60
2022	68
2023	41
2024	85
2025-2029	395
2030-2034	475
2035-2039	283
2040-2044	267
2045-2047	0
Net Par Outstanding (excluding loss mitigation bonds)	2,725	[4],[5]	$ 2,492
Estimated BIG Net Debt Service Amortization [Abstract]
2015 (July 1 - September 30)	276
2015 (October 1 - December 31)	35
2016	332
2017	289
2018	232
2019	232
2020	280
2021	147
2022	152
2023	123
2024	165
2025-2029	723
2030-2034	712
2035-2039	382
2040-2044	296
2045-2047	0
Total	$ 4,376

[1] Excludes $1.2 billion of loss mitigation securities insured and held by the Company as of June 30, 2015, which are primarily in the BIG category.

[2] amounts include $13.1 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 in the BIG category.

[4] In July 2015, various Puerto Rico issuers made payment on $293 million of par scheduled to be paid; of that amount, $74 million and $31 million of par was paid by PREPA and PRHTA, respectively.

[5] In Second Quarter 2015, the Company's Puerto Rico exposures increased due to (1) the Radian Asset Acquisition, which increased net par outstanding by $422 million, of which $22 million was for PREPA and $169 million for PRHTA, and (2) a commutation of previously ceded Puerto Rico exposures.