Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income		$ 5,855	$ 3,299	$ 3,704
Preferred stock dividends and other		(495)	(256)	(178)
Net Income Available to Common Stockholders		$ 5,360	$ 3,043	$ 3,526
Weighted-average common shares outstanding - basic (in shares)		1,887	1,429	1,311
Basic earnings per share (USD per share)	[1]	$ 2.84	$ 2.13	$ 2.69
Weighted-average common shares outstanding - diluted (in shares)		1,897	1,435	1,320
Diluted earnings per share (USD per share)	[1]	$ 2.83	$ 2.12	$ 2.67
Antidilutive stock options and restricted stock units excluded from the calculation of diluted EPS (in shares)		16	22	21
Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income		$ 5,610	$ 3,255	$ 3,704
Preferred stock dividends and other		(474)	(253)	(178)
Net Income Available to Common Stockholders		$ 5,136	$ 3,002	$ 3,526
Weighted-average common shares outstanding - basic (in shares)		1,808	1,410	1,311
Basic earnings per share (USD per share)		$ 2.84	$ 2.13	$ 2.69
Reallocation of net income available to common stockholders as a result of conversion of nonvoting to voting shares		$ 224	$ 41
Allocation of net income available to common stockholders:		$ 5,360	$ 3,043	$ 3,526
Conversion of nonvoting shares to voting shares (in shares)		79	19
Common stock equivalent shares related to stock incentive plans (in shares)		10	6	9
Weighted-average common shares outstanding - diluted (in shares)		1,897	1,435	1,320
Diluted earnings per share (USD per share)		$ 2.83	$ 2.12	$ 2.67
Nonvoting Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income		$ 245	$ 44
Preferred stock dividends and other		(21)	(3)
Net Income Available to Common Stockholders		$ 224	$ 41
Weighted-average common shares outstanding - basic (in shares)		79	19
Basic earnings per share (USD per share)		$ 2.84	$ 2.13
Reallocation of net income available to common stockholders as a result of conversion of nonvoting to voting shares		$ 0	$ 0
Allocation of net income available to common stockholders:		$ 224	$ 41
Conversion of nonvoting shares to voting shares (in shares)		0	0
Common stock equivalent shares related to stock incentive plans (in shares)		0	0
Weighted-average common shares outstanding - diluted (in shares)		79	19
Diluted earnings per share (USD per share)		$ 2.83	$ 2.12

[1] For the years ended December 31, 2021 and 2020, the Company had voting and nonvoting common stock outstanding. As the participation rights, including dividend and liquidation rights, are identical between the voting and nonvoting stock classes, basic and diluted earnings per share are the same for each class. See Notes 19 and 25 for additional information.