Noncontrolling Interests (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Activity for equity attributable to noncontrolling interests
Beginning Balance				$ 35,226	$ 40,082
Net income (loss)		$ 436	$ (1,026)	(2,391)	(3,540)
Dividends paid				(986)	(940)
Repurchase of company common stock				(2,045)	0
Distributions to noncontrolling interests				(84)	(75)
Other	[1]			992	929
Ending Balance		30,712	36,456	30,712	36,456
Common Stockholders' Equity [Member]
Activity for equity attributable to noncontrolling interests
Beginning Balance				34,974	39,762
Net income (loss)				(2,434)	(3,580)
Dividends paid				(986)	(940)
Repurchase of company common stock				(2,045)	0
Distributions to noncontrolling interests				0	0
Other	[1]			991	928
Ending Balance		30,500	36,170	30,500	36,170
Noncontrolling Interest [Member]
Activity for equity attributable to noncontrolling interests
Beginning Balance				252	320
Net income (loss)				43	40
Dividends paid				0	0
Repurchase of company common stock				0	0
Distributions to noncontrolling interests				(84)	(75)
Other	[1]			1	1
Ending Balance		$ 212	$ 286	$ 212	$ 286

[1] *Includes components of other comprehensive income (loss), which are disclosed separately in the Consolidated Statement of Comprehensive