Consolidated Statements of Changes in Equity (Deficit) - USD ($) shares in Millions, $ in Millions	Total	Senior Preferred Stock	Preferred Stock	Common Stock	Accumulated Deficit	Accumulated Other Comprehensive Income	Treasury Stock
Balance (shares) at Dec. 31, 2016		1	556	1,158
Balance at Dec. 31, 2016	$ (6,071)	$ (117,149)	$ (19,130)	$ (687)	$ 124,253	$ (759)	$ 7,401
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Senior preferred stock dividends paid per share	(12,015)				(12,015)
Proceeds from senior preferred stock purchase agreement with Treasury	0
Comprehensive income:
Net income	2,463				2,463
Other comprehensive income, net of tax effect:
Changes in net unrealized gains on available-for-sale securities (net of taxes of $28, $21 and $0, respectively)	53					53
Reclassification adjustment for gains included in net income (net of taxes of $139, $70 and $48, respectively)	(259)					(259)
Other, (net of taxes of $0, $0 and $3, respectively)	0
Other	1						1
Total comprehensive income	2,257
Balance at Dec. 31, 2017	3,686	$ (117,149)	$ (19,130)	$ (687)	133,805	(553)	7,400
Balance (shares) at Dec. 31, 2017		1	556	1,158
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Senior preferred stock dividends paid per share	(9,372)				(9,372)
Proceeds from senior preferred stock purchase agreement with Treasury	3,687	$ 3,687
Comprehensive income:
Net income	15,959				15,959
Other comprehensive income, net of tax effect:
Changes in net unrealized gains on available-for-sale securities (net of taxes of $28, $21 and $0, respectively)	(79)					(79)
Reclassification adjustment for gains included in net income (net of taxes of $139, $70 and $48, respectively)	(265)					(265)
Other, (net of taxes of $0, $0 and $3, respectively)	(4)					(4)
Total comprehensive income	15,611
Reclassification related to Tax Cuts and Jobs Act					(117)	117
Balance at Dec. 31, 2018	(6,240)	$ (120,836)	$ (19,130)	$ (687)	127,335	(322)	7,400
Balance (shares) at Dec. 31, 2018		1	556	1,158
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Senior preferred stock dividends paid per share	(5,601)				(5,601)
Proceeds from senior preferred stock purchase agreement with Treasury	0
Comprehensive income:
Net income	14,160				14,160
Other comprehensive income, net of tax effect:
Reclassification adjustment for gains included in net income (net of taxes of $139, $70 and $48, respectively)	1					1
Prior service cost and actuarial gains, net of amortization for defined benefit plans (net of tax)	(180)					(180)
Other, (net of taxes of $0, $0 and $3, respectively)	(12)					(12)
Total comprehensive income	13,969
Balance at Dec. 31, 2019	$ (14,608)	$ (120,836)	$ (19,130)	$ (687)	$ 118,776	$ (131)	$ 7,400
Balance (shares) at Dec. 31, 2019		1	556	1,158