Outstanding Exposure - Amortization Schedule of Puerto Rico BIG Net Par Outstanding and BIG Net Debt Service Outstanding (Details) - USD ($) $ in Millions	Dec. 31, 2016		Dec. 31, 2015
Estimated BIG Net Par Amortization [Abstract]
Net Par Outstanding	$ 296,318	[1]	$ 358,571	[2]
Estimated BIG Net Debt Service Amortization [Abstract]
Total	437,535		536,341
Puerto Rico [Member]
Estimated BIG Net Par Amortization [Abstract]
2017 (January 1 - March 31)	0
2017 (April 1 - June 30)	0
2017 (July 1 - September 30)	220
2017 (October 1 - December 31)	0
Subtotal 2017	220
2018	175
2019	206
2020	266
2021	125
2022-2026	869
2027-2031	889
2032-2036	1,201
2037-2041	417
2042-2047	418
Net Par Outstanding	4,786		$ 5,053
Estimated BIG Net Debt Service Amortization [Abstract]
2017 (January 1 - March 31)	118
2017 (April 1 - June 30)	2
2017 (July 1 - September 30)	339
2017 (October 1 - December 31)	2
Subtotal 2017	461
2018	408
2019	429
2020	480
2021	326
2022-2026	1,759
2027-2031	1,534
2032-2036	1,612
2037-2041	588
2042-2047	492
Total	$ 8,089

[1] The December 31, 2016 amounts include $2.9 billion of net par from the CIFG Acquisition.

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