Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Basic earnings per share
Net income	$ 32,474	$ 24,441	$ 24,733
Less: Preferred stock dividends	1,551	1,663	1,647
Net income applicable to common equity	30,923	22,778	23,086
Less: Dividends and undistributed earnings allocated to participating securities	214	211	252
Net income applicable to common stockholders	$ 30,709	$ 22,567	$ 22,834
Total weighted-average basic shares outstanding (in shares)	3,396.4	3,551.6	3,658.8
Net income per share (in dollars per share)	$ 9.04	$ 6.35	$ 6.24
Diluted earnings per share
Net income applicable to common stockholders	$ 30,709	$ 22,567	$ 22,834
Total weighted-average basic shares outstanding (in shares)	3,396.4	3,551.6	3,658.8
Add: Employee stock options, SARs, warrants and unvested PSUs (in shares)	17.6	25.2	31.2
Total weighted-average diluted shares outstanding (in shares)	3,414.0	3,576.8	3,690.0
Net income per share (in dollars per share)	$ 9.00	$ 6.31	$ 6.19