CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income/(loss)	$ 85,522	$ (908,995)
Other Comprehensive (Loss):
Unrealized (losses)/gains on securities available-for-sale	(3,855)	124,410
Reclassification adjustment for securities sales included in net income	0	(23,953)
Reclassification adjustment for impairments included in net income	0	(344,269)
Derivative hedging instrument fair value changes, net	0	(50,127)
Changes in fair value of financing agreements at fair value due to changes in instrument-specific credit risk	235	0
Reclassification adjustment for losses related to hedging instruments included in net income	0	1,594
Other Comprehensive (Loss)	(3,620)	(292,345)
Comprehensive income/(loss) before preferred stock dividends	81,902	(1,201,340)
Dividends required on preferred stock	(8,219)	(5,215)
Comprehensive Income/(Loss) Available to Common Stock and Participating Securities	$ 73,683	$ (1,206,555)