Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Basic earnings per share
Net income	$ 8,282	$ 14,300
Less: Preferred stock dividends	397	379
Net income applicable to common equity	7,885	13,921
Less: Dividends and undistributed earnings allocated to participating securities	40	70
Net income applicable to common stockholders	$ 7,845	$ 13,851
Total weighted-average basic shares outstanding (in shares)	2,977.0	3,073.5
Net income per share (in dollars per share)	$ 2.64	$ 4.51
Diluted earnings per share
Net income applicable to common stockholders	$ 7,845	$ 13,851
Total weighted-average basic shares outstanding (in shares)	2,977.0	3,073.5
Add: Dilutive impact of SARs and employee stock options, unvested PSUs and nondividend-earning RSUs (in shares)	4.0	5.4
Total weighted-average diluted shares outstanding (in shares)	2,981.0	3,078.9
Net income per share (in dollars per share)	$ 2.63	$ 4.50