Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Basic earnings per share
Net income	$ 24,733	$ 24,442	$ 21,745
Less: Preferred stock dividends	1,647	1,515	1,125
Net income applicable to common equity	23,086	22,927	20,620
Less: Dividends and undistributed earnings allocated to participating securities	503	521	543
Net income applicable to common stockholders	$ 22,583	$ 22,406	$ 20,077
Total weighted-average basic shares outstanding (in shares)	3,618.5	3,700.4	3,763.5
Net income per share (in dollars per share)	$ 6.24	$ 6.05	$ 5.33
Diluted earnings per share
Net income applicable to common stockholders	$ 22,583	$ 22,406	$ 20,077
Total weighted-average basic shares outstanding (in shares)	3,618.5	3,700.4	3,763.5
Add: Employee stock options, SARs, warrants, and PSUs (in shares)	31.3	32.4	34.0
Total weighted-average diluted shares outstanding (in shares)	3,649.8	3,732.8	3,797.5
Net income per share (in dollars per share)	$ 6.19	$ 6.00	$ 5.29
Earnings Per Share, Diluted, Other Disclosures [Abstract]
Antidilutive securities excluded from computation of earnings per share (in shares)			1.0