Earnings Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Basic EPS Calculation
Earnings available to common stockholders – Basic	$ 26,179	[1]	$ 26,895	[1]	$ 19,024	[1]
Weighted-average number of common shares outstanding	1,950		1,986		1,996
Add: Deferred awards held as stock units	0		0		1
Total weighted-average number of common shares outstanding	1,950		1,986		1,997
Earnings per share of common stock - Basic	$ 13.42		$ 13.54		$ 9.53
Diluted EPS Calculation
Earnings available to common stockholders - Diluted	$ 26,179	[1]	$ 26,895	[1]	$ 19,024	[1]
Weighted-average number of common shares outstanding	1,950		1,986		1,996
Add: Deferred awards held as stock units	0		0		1
Add: Deferred awards held as stock units	15		15		10
Total weighted-average number of common shares outstanding	1,965		2,001		2,007
Earnings per share of common stock - Diluted	$ 13.32		$ 13.44		$ 9.48

[1] There was no effect of dividend equivalents paid on stock units or dilutive impact of employee stock-based awards on earnings.