Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (USD $) In Millions, except Share data, unless otherwise specified	Total	Series C Preferred Stock	Preferred Stock	Preferred Stock Series C Preferred Stock	Common Stock	Additional Paid-In Capital	Additional Paid-In Capital Series C Preferred Stock	Retained Earnings		Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance at Dec. 31, 2013	$ 41,632		$ 0		$ 6	$ 26,526		$ 20,292	[1]	$ (872)	$ (4,320)
Beginning balance (shares) at Dec. 31, 2013			875,000		637,151,800
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	3,742							3,429	[1]	313
Cash dividends—common stock $0.90 per share	(513)							(513)	[1]
Cash dividends - preferred series B stock 6%, series C stock 6.25% per annum	(46)							(46)	[1]
Purchases of treasury stock	(1,543)										(1,543)
Issuances of common stock and restricted stock, net of forfeitures	73				0	73
Issuances of common stock and restricted stock, net of forfeitures (in shares)					1,078,458
Exercise of stock options and warrants, tax benefits of exercises and restricted stock vesting	89				0	89
Exercise of stock options and warrants, tax benefits of exercises and restricted stock vesting (in shares)					4,287,002
Issuances of preferred stock (Series C)		484		0			484
Issuances of preferred stock (Series C) (in shares)				500,000
Compensation expense for restricted stock awards and stock options	100					100
Ending balance at Sep. 30, 2014	$ 44,018		$ 0		$ 6	$ 27,272		$ 23,162	[1]	$ (559)	$ (5,863)
Ending balance (shares) at Sep. 30, 2014			1,375,000		642,517,260

[1] Retained earnings as of December 31, 2013 includes the cumulative impact of $112 million resulting from the adoption of ASU 2014-01 “Accounting For Investments in Qualified Affordable Housing Projects.” See “Note 1—Summary of Significant Accounting Policies” for additional information.