Shareholders' Equity (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended		9 Months Ended
	Aug. 31, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Shareholders' equity activity [Roll Forward]
Balance at beginning of period				$ 15,790	$ 13,216
Shares repurchased	(3,300)			(4,356)
Stock plans				397	265
Payments of dividends to shareholders				(337)	(250)
Other				(25)	(24)
Comprehensive income (loss)		710	603	1,349	1,984
Balance at end of period		12,818	15,191	12,818	15,191
Company shareholders' equity
Shareholders' equity activity [Roll Forward]
Balance at beginning of period				15,765	13,198
Shares repurchased				(4,356)
Stock plans				397	265
Payments of dividends to shareholders				(337)	(250)
Other				(22)	(22)
Comprehensive income (loss)				1,341	1,977
Balance at end of period		12,788	15,168	12,788	15,168
Noncontrolling interest in consolidated subsidiaries
Shareholders' equity activity [Roll Forward]
Balance at beginning of period				25	18
Shares repurchased				0
Stock plans				0	0
Payments of dividends to shareholders				0	0
Other				(3)	(2)
Comprehensive income (loss)				8	7
Balance at end of period		$ 30	$ 23	$ 30	$ 23