Subsequent Events (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Subsequent Events [Line Items]
Net interest income	$ 5,559		$ 5,317		$ 5,428		$ 5,197		$ 4,163	$ 5,186	$ 4,972	$ 4,960	$ 21,501	$ 19,281	$ 16,409
Benefit for credit losses	1,890	[1]	(2,079)	[1]	3,041	[1]	(2,000)	[1]	(5,476)	(4,151)	(6,537)	(10,554)	852	(26,718)	(24,896)
Foreclosed property income (expense)	475		48		70		(339)		(37)	(733)	478	(488)	254	(780)	(1,718)
Total									(2,406)	(5,085)	(2,985)	(6,469)	17,220	(16,945)	(14,100)
Subsequent Events [Member] | Repurchase Request Resolution Agreement [Member]
Subsequent Events [Line Items]
Net interest income													181
Benefit for credit losses													841
Foreclosed property income (expense)													106
Total													$ 1,128

[1] Includes out-of-period adjustments of $548 million, $503 million, $850 million, and $172 million which increased our provision for credit losses for the three months ended March 31, 2012, June 30, 2012, September 30, 2012, and December 31, 2012, respectively.