Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (USD $) In Millions, unless otherwise specified	Total	Preferred stock	Common stock	Capital surplus	Retained earnings	Accumulated other comprehensive income/(loss)	Shares held in RSU Trust, at cost	Treasury stock, at cost
Beginning balance at Dec. 31, 2011		$ 7,800	$ 4,105	$ 95,602	$ 88,315	$ 944	$ (38)	$ (13,155)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of preferred stock		0
Shares issued and commitments to issue common stock for employee stock-based compensation awards, and related tax effects				(1,163)
Other				(238)
Net income	9,884				9,884
Dividends declared:
Preferred stock					(315)
Common stock ($0.68 and $0.60 per share)					(2,366)
Other comprehensive (loss)/income	1,328					1,328
Purchase of treasury stock								(1,415)
Reissuance from treasury stock								2,284
Ending balance at Jun. 30, 2012	191,572	7,800	4,105	94,201	95,518	2,272	(38)	(12,286)
Beginning balance at Mar. 31, 2012
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	4,960
Dividends declared:
Other comprehensive (loss)/income	(373)					(373)
Ending balance at Jun. 30, 2012	191,572		4,105			2,272	(38)
Beginning balance at Dec. 31, 2012		9,058	4,105	94,604	104,223	4,102	(21)	(12,002)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of preferred stock		2,400
Shares issued and commitments to issue common stock for employee stock-based compensation awards, and related tax effects				(1,164)
Other				(24)
Net income	13,025				13,025
Dividends declared:
Preferred stock					(386)
Common stock ($0.68 and $0.60 per share)					(2,646)
Other comprehensive (loss)/income	(3,966)					(3,966)
Purchase of treasury stock								(3,750)
Reissuance from treasury stock								1,681
Ending balance at Jun. 30, 2013	209,239	11,458	4,105	93,416	114,216	136	(21)	(14,071)
Beginning balance at Mar. 31, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	6,496
Dividends declared:
Other comprehensive (loss)/income	(3,355)					(3,355)
Ending balance at Jun. 30, 2013	$ 209,239		$ 4,105			$ 136	$ (21)