Shareholders' Equity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Shareholders' equity activity [Roll Forward]
Balance at beginning of period			$ 16,298	$ 13,615
Shares repurchased				(800)
Stock plans			380	505
Payments of dividends to shareholders			(460)	(381)
Other			(45)	(17)
Comprehensive income (loss)	$ (206)	$ 1,201	(693)	2,596
Balance at end of period	15,480	15,518	15,480	15,518
Company shareholders' equity
Shareholders' equity activity [Roll Forward]
Balance at beginning of period			16,267	13,581
Shares repurchased				(800)
Stock plans			380	505
Payments of dividends to shareholders			(460)	(381)
Other			(44)	(13)
Comprehensive income (loss)			(695)	2,599
Balance at end of period	15,448	15,491	15,448	15,491
Noncontrolling interest in consolidated subsidiaries
Shareholders' equity activity [Roll Forward]
Balance at beginning of period			31	34
Shares repurchased				0
Stock plans			0	0
Payments of dividends to shareholders			0	0
Other			(1)	(4)
Comprehensive income (loss)			2	(3)
Balance at end of period	$ 32	$ 27	$ 32	$ 27