Background and Business Description Puerto Rico (Details)	Sep. 30, 2017
FEGP Implied Discount on Debt Service	77.00%
GO Maximum Recovery Percent	77.00%
COFINA Maximum Recovery Percent	58.00%
Metropolitan Bus Authority Maximum Recovery Percent	30.00%
Litigation Related to Puerto Rico Exposures	10
Senior Debt Obligations [Member]
GO Maximum Recovery Percent	52.00%
COFINA Maximum Recovery Percent	39.00%
Metropolitan Bus Authority Maximum Recovery Percent	0.00%
Cash Flow Bond [Domain]
GO Maximum Recovery Percent	25.00%
COFINA Maximum Recovery Percent	19.00%
Metropolitan Bus Authority Maximum Recovery Percent	30.00%
Challenging Constitutionality of FEPG [Domain]
Litigation Related to Puerto Rico Exposures	3
Stayed Under Title III of PROMESA [Domain]
Litigation Related to Puerto Rico Exposures	6
Stayed Pending Resolution of Action Related to COFINA [Domain]
Litigation Related to Puerto Rico Exposures	1
Active Litigation Under Title III Process [Domain]
Litigation Related to Puerto Rico Exposures	3