Common Stock - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Mar. 11, 2015	Jun. 30, 2014
Class of Stock [Line Items]
Common stock, shares authorized (in shares)		9,000,000,000	9,000,000,000
Common stock, par value (in dollars per share)		$ 1	$ 1.00
Original warrant exercisable price (in dollars per share)		42.284				$ 42.42
Common stock quarterly dividend (in dollars per share)		$ 1.72	$ 1.58	$ 1.44
Stock repurchase program, shares authorized					$ 6,400,000,000
Remaining authorized repurchase amount		$ 2,700,000,000
Warrant | JPMorgan Chase & Co.
Class of Stock [Line Items]
Warrants outstanding (in shares)		47,400,000	59,800,000	59,800,000
Common stock
Class of Stock [Line Items]
Common stock quarterly dividend (in dollars per share)	$ 0.38
Common stock capital shares reserved for future issuance (shares)		195,000,000