Earnings Per Common Share - Earnings per Share under Basic and Diluted Computations (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income	[1]	$ 5,067	$ 7,183	$ 5,855
Preferred stock dividends and other		(418)	(548)	(495)
Net Income Available to Common Stockholders		$ 4,649	$ 6,635	$ 5,360
Weighted-average common shares outstanding - basic (in shares)		1,824	1,885	1,887
Basic earnings per share (in USD per share)	[2]	$ 2.55	$ 3.52	$ 2.84
Weighted-average common shares outstanding - diluted (in shares)		1,831	1,894	1,897
Diluted earnings per share (in USD per share)	[2]	$ 2.54	$ 3.50	$ 2.83
Antidilutive stock options and restricted stock units excluded from the calculation of diluted EPS (in shares)		19	15	16
Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income		$ 4,925	$ 6,926	$ 5,610
Preferred stock dividends and other		(406)	(528)	(474)
Net Income Available to Common Stockholders		$ 4,519	$ 6,398	$ 5,136
Weighted-average common shares outstanding - basic (in shares)		1,773	1,818	1,808
Basic earnings per share (in USD per share)		$ 2.55	$ 3.52	$ 2.84
Reallocation of net income available to common stockholders as a result of conversion of nonvoting to voting shares		$ 130	$ 237	$ 224
Allocation of net income available to common stockholders:		$ 4,649	$ 6,635	$ 5,360
Conversion of nonvoting shares to voting shares (in shares)		51	67	79
Common stock equivalent shares related to stock incentive plans (in shares)		7	9	10
Weighted-average common shares outstanding - diluted (in shares)		1,831	1,894	1,897
Diluted earnings per share (in USD per share)		$ 2.54	$ 3.50	$ 2.83
Nonvoting Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income		$ 142	$ 257	$ 245
Preferred stock dividends and other		(12)	(20)	(21)
Net Income Available to Common Stockholders		$ 130	$ 237	$ 224
Weighted-average common shares outstanding - basic (in shares)		51	67	79
Basic earnings per share (in USD per share)		$ 2.55	$ 3.52	$ 2.84
Reallocation of net income available to common stockholders as a result of conversion of nonvoting to voting shares		$ 0	$ 0	$ 0
Allocation of net income available to common stockholders:		$ 130	$ 237	$ 224
Conversion of nonvoting shares to voting shares (in shares)		0	0	0
Common stock equivalent shares related to stock incentive plans (in shares)		0	0	0
Weighted-average common shares outstanding - diluted (in shares)		51	67	79
Diluted earnings per share (in USD per share)		$ 2.54	$ 3.50	$ 2.83

[1] Certain prior year amounts have been reclassified to conform to the current year presentation. See Note 1 for additional information.

[2] The Company has 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.