Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Basic earnings per share
Net income	$ 9,179	$ 8,712
Less: Preferred stock dividends	374	409
Net income applicable to common equity	8,805	8,303
Less: Dividends and undistributed earnings allocated to participating securities	52	65
Net income applicable to common stockholders	$ 8,753	$ 8,238
Total weighted-average basic shares outstanding (in shares)	3,298.0	3,458.3
Net income per share (in dollars per share)	$ 2.65	$ 2.38
Diluted earnings per share
Net income applicable to common stockholders	$ 8,753	$ 8,238
Total weighted-average basic shares outstanding (in shares)	3,298.0	3,458.3
Add: Employee stock options, SARs, warrants and unvested PSUs (in shares)	10.2	21.2
Total weighted-average diluted shares outstanding (in shares)	3,308.2	3,479.5
Net income per share (in dollars per share)	$ 2.65	$ 2.37