Shareholders' Equity (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Shareholders' equity activity [Roll Forward]
Balance at beginning of period		$ 15,715	$ 15,495	$ 16,298
Stock plans			244	254
Payments of dividends to shareholders			(309)	(306)
Other			(32)	(44)
Comprehensive income (loss)	$ (3,202)	157	(5,621)	(487)
Balance at end of period	9,777		9,777
Company shareholders' equity
Shareholders' equity activity [Roll Forward]
Balance at beginning of period		15,685	15,462	16,267
Stock plans			244	254
Payments of dividends to shareholders			(309)	(306)
Other			(45)	(42)
Comprehensive income (loss)			(5,618)	(488)
Balance at end of period	9,734		9,734
Noncontrolling interest in consolidated subsidiaries
Shareholders' equity activity [Roll Forward]
Balance at beginning of period		$ 30	33	31
Stock plans			0	0
Payments of dividends to shareholders			0	0
Other			13	(2)
Comprehensive income (loss)			(3)	$ 1
Balance at end of period	$ 43		$ 43