Consolidated Statements Of Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Dividends declared per common share	$ 0.36	$ 0.50	$ 0.84	$ 1.04
Interest income:
Interest income	$ 429	$ 693	$ 920	$ 1,398
Interest expense	134	570	560	1,111
Net interest income	295	123	360	287
Other gain (loss), net:
Gain on sale of investment securities, net	153	132	647	192
Unrealized gain on investment securities measured at fair value through net income, net	679	759	876	1,819
Loss on derivative instruments and other securities, net	(385)	(1,438)	(3,539)	(2,438)
Total other gain (loss), net:	447	(547)	(2,016)	(427)
Expenses:
Compensation and benefits	13	11	26	21
Other operating expense	11	9	21	18
Total operating expense	24	20	47	39
Net income (loss)	718	(444)	(1,703)	(179)
Dividend on preferred stock	25	13	46	23
Net income (loss) available (attributable) to common stockholders	693	(457)	(1,749)	(202)
Other comprehensive income (loss):
Unrealized gain on investment securities measured at fair value through other comprehensive income, net	(203)	(379)	(667)	(779)
Comprehensive income (loss)	921	(65)	(1,036)	600
Comprehensive income (loss) available (attributable) to common stockholders	$ 896	$ (78)	$ (1,082)	$ 577
Weighted average number of common shares outstanding - basic	560.3	537.8	554.2	537.2
Weighted average number of common shares outstanding - diluted	560.8	537.8	554.2	537.2
Net income (loss) per common share - basic	$ 1.24	$ (0.85)	$ (3.16)	$ (0.38)
Net income (loss) per common share - diluted	$ 1.24	$ (0.85)	$ (3.16)	$ (0.38)