TWO Annual report pursuant to Section 13 and 15(d)

Schedule of Available-for-sale Securities Reconciliation (Details)

Schedule of Available-for-sale Securities Reconciliation (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Principal/ Current Face	$ 29,396,680	$ 16,290,758
Unamortized Premium	1,370,959	826,062
Accretable Purchase Discount	(700,671)	(674,303)
Credit Reserve Purchase Discount	(653,613)	(367,437)
Amortized Cost	20,856,658	12,927,650
Unrealized Gain	544,198	432,398
Unrealized Loss	(180,037)	(243,877)
Available-for-sale securities, at fair value	21,220,819	13,116,171
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Principal/ Current Face	20,023,621	13,571,417
Unamortized Premium	1,302,535	818,122
Accretable Purchase Discount	(24,638)	(42,923)
Credit Reserve Purchase Discount	0	0
Amortized Cost	18,359,746	11,384,721
Unrealized Gain	53,104	79,040
Unrealized Loss	(174,125)	(237,287)
Available-for-sale securities, at fair value	18,238,725	11,226,474
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Fixed Income Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Principal/ Current Face	17,081,849	10,609,522
Unamortized Premium	1,079,246	571,749
Accretable Purchase Discount	(24,638)	(42,923)
Credit Reserve Purchase Discount	0	0
Amortized Cost	18,136,457	11,138,348
Unrealized Gain	42,149	66,968
Unrealized Loss	(134,969)	(208,190)
Available-for-sale securities, at fair value	18,043,637	10,997,126
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Interest-Only-Strip [Member]
Schedule of Available-for-sale Securities [Line Items]
Principal/ Current Face	2,941,772	2,961,895
Unamortized Premium	223,289	246,373
Accretable Purchase Discount	0	0
Credit Reserve Purchase Discount	0	0
Amortized Cost	223,289	246,373
Unrealized Gain	10,955	12,072
Unrealized Loss	(39,156)	(29,097)
Available-for-sale securities, at fair value	195,088	229,348
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Principal/ Current Face	9,373,059	2,719,341
Unamortized Premium	68,424	7,940
Accretable Purchase Discount	(676,033)	(631,380)
Credit Reserve Purchase Discount	(653,613)	(367,437)
Amortized Cost	2,496,912	1,542,929
Unrealized Gain	491,094	353,358
Unrealized Loss	(5,912)	(6,590)
Available-for-sale securities, at fair value	2,982,094	1,889,697
Mortgage-backed Securities, Issued by Private Enterprises [Member] \| Fixed Income Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Principal/ Current Face	3,758,134	2,533,806
Unamortized Premium	2,757	3,577
Accretable Purchase Discount	(676,033)	(631,380)
Credit Reserve Purchase Discount	(653,613)	(367,437)
Amortized Cost	2,431,245	1,538,566
Unrealized Gain	488,931	353,240
Unrealized Loss	(3,166)	(6,386)
Available-for-sale securities, at fair value	2,917,010	1,885,420
Mortgage-backed Securities, Issued by Private Enterprises [Member] \| Interest-Only-Strip [Member]
Schedule of Available-for-sale Securities [Line Items]
Principal/ Current Face	5,614,925	185,535
Unamortized Premium	65,667	4,363
Accretable Purchase Discount	0	0
Credit Reserve Purchase Discount	0	0
Amortized Cost	65,667	4,363
Unrealized Gain	2,163	118
Unrealized Loss	(2,746)	(204)
Available-for-sale securities, at fair value	$ 65,084	$ 4,277