Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Basic earnings per share
Net income	$ 11,948	$ 4,687	$ 26,248	$ 7,552
Less: Preferred stock dividends	393	401	772	822
Net income applicable to common equity	11,555	4,286	25,476	6,730
Less: Dividends and undistributed earnings allocated to participating securities	59	21	130	32
Net income applicable to common stockholders	$ 11,496	$ 4,265	$ 25,346	$ 6,698
Total weighted-average basic shares outstanding (in shares)	3,036.6	3,076.3	3,054.9	3,086.1
Net income per share (in dollars per share)	$ 3.79	$ 1.39	$ 8.30	$ 2.17
Diluted earnings per share
Net income applicable to common stockholders	$ 11,496	$ 4,265	$ 25,346	$ 6,698
Total weighted-average basic shares outstanding (in shares)	3,036.6	3,076.3	3,054.9	3,086.1
Add: Dilutive impact of SARs and employee stock options, unvested PSUs and nondividend-earning RSUs (in shares)	5.3	4.7	5.4	4.7
Total weighted-average diluted shares outstanding (in shares)	3,041.9	3,081.0	3,060.3	3,090.8
Net income per share (in dollars per share)	$ 3.78	$ 1.38	$ 8.28	$ 2.17