Shareholders' Equity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Shareholders' equity activity [Roll Forward]
Balance at beginning of period			$ 15,495	$ 16,298
Stock plans			348	380
Payments of dividends to shareholders			(465)	(460)
Other			(39)	(45)
Comprehensive income (loss)	$ 8	$ (206)	(5,613)	(693)
Balance at end of period	9,726	15,480	9,726	15,480
Company shareholders' equity
Shareholders' equity activity [Roll Forward]
Balance at beginning of period			15,462	16,267
Stock plans			348	380
Payments of dividends to shareholders			(465)	(460)
Other			(52)	(44)
Comprehensive income (loss)			(5,611)	(695)
Balance at end of period	9,682	15,448	9,682	15,448
Noncontrolling interest in consolidated subsidiaries
Shareholders' equity activity [Roll Forward]
Balance at beginning of period			33	31
Stock plans			0	0
Payments of dividends to shareholders			0	0
Other			13	(1)
Comprehensive income (loss)			(2)	2
Balance at end of period	$ 44	$ 32	$ 44	$ 32