Outstanding Exposure - Amortization Schedule of Puerto Rico Net Par Outstanding and Net Debt Service Outstanding (Details) - USD ($) $ in Millions	Jun. 30, 2016		Dec. 31, 2015
Estimated Net Par Amortization [Abstract]
Net par amount outstanding	$ 329,864	[1]	$ 358,571	[2]
Estimated Net Debt Service Amortization [Abstract]
Total	488,362		536,341
Puerto Rico [Member]
Estimated Net Par Amortization [Abstract]
2016 (July 1 – September 30)	302
2016 (October 1 – December 31)	0
2017	222
2018	179
2019	204
2020	270
2021	125
2022	115
2023	150
2024	174
2025	196
2026-2030	943
2031-2035	1,131
2036-2040	579
2041-2045	296
2046-2047	168
Net par amount outstanding	5,054		5,053
Estimated Net Debt Service Amortization [Abstract]
2016 (July 1 – September 30)	428
2016 (October 1 – December 31)	2
2017	463
2018	410
2019	424
2020	482
2021	323
2022	305
2023	338
2024	352
2025	366
2026-2030	1,633
2031-2035	1,599
2036-2040	780
2041-2045	380
2046-2047	181
Total	8,466
BIG [Member]
Estimated Net Par Amortization [Abstract]
Net par amount outstanding	14,790		$ 15,183
BIG [Member] | Puerto Rico [Member]
Estimated Net Par Amortization [Abstract]
Net par amount outstanding	$ 5,100

[1] Excludes $1.4 billion of loss mitigation securities insured and held by the Company as of June 30, 2016, which are primarily BIG.

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