CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Millions		Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Cumulative Effect, Period of Adoption, Adjustment [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings	Cumulative Effect, Period of Adoption, Adjustment [Member] Accumulated Other Comprehensive Income (Loss)
Beginning balance (shares) at Dec. 31, 2018			4,475,000	667,969,069
Beginning balance at Dec. 31, 2018		$ 51,668	$ 0	$ 7	$ 32,040	$ 35,875	$ (1,263)	$ (14,991)	$ (11)	$ (11)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)		7,077				5,546	1,531
Effects from transfer of securities held to maturity to available for sale		888					888
Dividends, common stock (shares)	[1]			49,963
Dividends, common stock	[1]	(753)		$ 0	4	(757)
Dividends, preferred stock		(282)				(282)
Purchases of treasury stock		(1,481)						(1,481)
Issuances of common stock and restricted stock, net of forfeitures (shares)				4,678,940
Issuances of common stock and restricted stock, net of forfeitures		199		$ 0	199
Exercises of stock options (shares)				271,419
Exercises of stock options		17		$ 0	17
Issuances of preferred stock (shares)			1,500,000
Issuances of preferred stock		1,462	$ 0		1,462
Redemptions of preferred stock (shares)			(1,000,000)
Redemptions of preferred stock		(1,000)	$ 0		(969)	(31)
Compensation expense for restricted stock units and stock options		227			227
Ending balance (shares) at Dec. 31, 2019			4,975,000	672,969,391
Ending balance at Dec. 31, 2019		58,011	$ 0	$ 7	32,980	40,340	1,156	(16,472)	$ (2,192)	$ (2,184)	$ (8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)		5,060				2,714	2,346
Dividends, common stock (shares)	[1]			32,466
Dividends, common stock	[1]	(460)		$ 0	3	(463)
Dividends, preferred stock		(280)				(280)
Purchases of treasury stock		(393)						(393)
Issuances of common stock and restricted stock, net of forfeitures (shares)				5,539,010
Issuances of common stock and restricted stock, net of forfeitures		241		$ 0	241
Exercises of stock options (shares)				1,391,970
Exercises of stock options		62		$ 0	62
Issuances of preferred stock (shares)			1,375,000
Issuances of preferred stock		1,330	$ 0		1,330
Redemptions of preferred stock (shares)			(1,375,000)
Redemptions of preferred stock		(1,375)	$ 0		(1,336)	(39)
Compensation expense for restricted stock units and stock options		200			200
Ending balance (shares) at Dec. 31, 2020			4,975,000	679,932,837
Ending balance at Dec. 31, 2020		60,204	$ 0	$ 7	33,480	40,088	3,494	(16,865)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)		9,270				12,390	(3,120)
Dividends, common stock (shares)	[1]			28,410
Dividends, common stock	[1]	(1,148)		$ 0	4	(1,152)
Dividends, preferred stock		(274)				(274)
Purchases of treasury stock		(7,605)						(7,605)
Issuances of common stock and restricted stock, net of forfeitures (shares)				4,178,919
Issuances of common stock and restricted stock, net of forfeitures		253		$ 0	253
Exercises of stock options (shares)				917,778
Exercises of stock options		55		$ 0	55
Issuances of preferred stock (shares)			2,100,000
Issuances of preferred stock		2,052	$ 0		2,052
Redemptions of preferred stock (shares)			(2,100,000)
Redemptions of preferred stock		(2,100)	$ 0		(2,054)	(46)
Compensation expense for restricted stock units and stock options		322			322
Ending balance (shares) at Dec. 31, 2021			4,975,000	685,057,944
Ending balance at Dec. 31, 2021		$ 61,029	$ 0	$ 7	$ 34,112	$ 51,006	$ 374	$ (24,470)

[1] We declared dividends per share on our common stock of $0.60 in the fourth quarter of 2021, $1.20 in the third quarter of 2021, $0.10 in both of the latter two quarters of 2020 and $0.40 in the first two quarters of 2021 and 2020 and each quarter of 2019.