Outstanding Exposure - Amortization Schedule of Puerto Rico BIG Net Par Outstanding and BIG Net Debt Service Outstanding (Details) - USD ($) $ in Millions	Sep. 30, 2015		Dec. 31, 2014
Estimated BIG Net Par Amortization [Abstract]
Net Par Outstanding (excluding loss mitigation bonds)	$ 372,361	[1],[2]	$ 403,729	[3]
Estimated BIG Net Debt Service Amortization [Abstract]
Total	556,381		609,622
Puerto Rico [Member]
Estimated BIG Net Par Amortization [Abstract]
2015 (October 1 - December 31)	33
2016	302
2017	222
2018	179
2019	204
2020	270
2021	125
2022	115
2023	151
2024	174
2025-2029	1,014
2030-2034	980
2035-2039	713
2040-2044	363
2045-2047	246
Net Par Outstanding (excluding loss mitigation bonds)	5,091	[4]	4,939
Estimated BIG Net Debt Service Amortization [Abstract]
2015 (October 1 - December 31)	36
2016	559
2017	464
2018	410
2019	424
2020	482
2021	323
2022	305
2023	337
2024	352
2025-2029	1,755
2030-2034	1,501
2035-2039	953
2040-2044	468
2045-2047	272
Total	8,641
BIG [Member]
Estimated BIG Net Par Amortization [Abstract]
Net Par Outstanding (excluding loss mitigation bonds)	17,611		18,247
Subject to the Terms of the Recovery Act [Member] | Puerto Rico [Member]
Estimated BIG Net Par Amortization [Abstract]
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	506
2035-2039	429
2040-2044	97
2045-2047	246
Net Par Outstanding (excluding loss mitigation bonds)	2,575	[4]	2,447
Estimated BIG Net Debt Service Amortization [Abstract]
2015 (October 1 - December 31)	2
2016	229
2017	175
2018	178
2019	192
2020	202
2021	176
2022	153
2023	214
2024	188
2025-2029	1,032
2030-2034	788
2035-2039	569
2040-2044	171
2045-2047	272
Total	4,541
Not Subject to the Terms of the Recovery Act [Member] | Puerto Rico [Member]
Estimated BIG Net Par Amortization [Abstract]
2015 (October 1 - December 31)	33
2016	204
2017	171
2018	123
2019	130
2020	183
2021	59
2022	68
2023	41
2024	85
2025-2029	395
2030-2034	474
2035-2039	284
2040-2044	266
2045-2047	0
Net Par Outstanding (excluding loss mitigation bonds)	2,516	[4]	$ 2,492
Estimated BIG Net Debt Service Amortization [Abstract]
2015 (October 1 - December 31)	34
2016	330
2017	289
2018	232
2019	232
2020	280
2021	147
2022	152
2023	123
2024	164
2025-2029	723
2030-2034	713
2035-2039	384
2040-2044	297
2045-2047	0
Total	$ 4,100

[1] Excludes $1.6 billion of loss mitigation securities insured and held by the Company as of September 30, 2015, which are primarily BIG.

[2] The September 30, 2015 amounts include $12.4 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] $385 million acquired in the Radian Asset Acquisition, of which $21 million was of PREPA and $166 million