Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Basic earnings per share
Net income	$ 9,652	$ 8,316	$ 18,831	$ 17,028
Less: Preferred stock dividends	404	379	778	788
Net income applicable to common equity	9,248	7,937	18,053	16,240
Less: Dividends and undistributed earnings allocated to participating securities	56	57	108	121
Net income applicable to common stockholders	$ 9,192	$ 7,880	$ 17,945	$ 16,119
Total weighted-average basic shares outstanding (in shares)	3,250.6	3,415.2	3,274.3	3,436.7
Net income per share (in dollars per share)	$ 2.83	$ 2.31	$ 5.48	$ 4.69
Diluted earnings per share
Net income applicable to common stockholders	$ 9,192	$ 7,880	$ 17,945	$ 16,119
Total weighted-average basic shares outstanding (in shares)	3,250.6	3,415.2	3,274.3	3,436.7
Add: Employee stock options, SARs, warrants and unvested PSUs (in shares)	9.1	19.5	9.6	20.4
Total weighted-average diluted shares outstanding (in shares)	3,259.7	3,434.7	3,283.9	3,457.1
Net income per share (in dollars per share)	$ 2.82	$ 2.29	$ 5.46	$ 4.66