Consolidated Statements of Changes in Total Equity - USD ($) $ in Millions	Total	Shareholders' Equity [Member]	Common Stock [Member]	Additional Paid In Capital [Member]	Accumulated Other Comprehensive Income [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Other noncontrolling interests [Member]
Total Equity, beginning of period at Dec. 31, 2014	$ 10,789	$ 10,774	$ 74	$ 2,769	$ (936)	$ 10,289	$ (1,422)	$ 15
Increase (Decrease) In Stockholders Equity [Roll Forward]
Effect of issuing stock for employee benefit plans	183	183		99		(252)	336
Other comprehensive income (loss)	(315)	(314)			(314)			(1)
Net income (loss)	2,083	2,094				2,094		(11)
Common dividends declared (per share: $0.04)	(10)	(10)				(10)
Repurchase of common stock	(683)	(683)					(683)
Other transactions impacting noncontrolling interest	(3)	(9)		(9)				6
Total Equity, end of period at Dec. 31, 2015	12,044	12,035	74	2,859	(1,250)	12,121	(1,769)	9
Beginning Balance at Dec. 31, 2014	90
Redeemable Noncontrolling Interests
Other comprehensive income (loss)	(17)
Net income (loss)	(6)
Other transactions impacting noncontrolling interest	2
Ending Balance at Dec. 31, 2015	69
Increase (Decrease) In Stockholders Equity [Roll Forward]
Effect of issuing stock for employee benefit plans	91	91		51		(123)	163
Other comprehensive income (loss)	(132)	(132)			(132)
Net income (loss)	1,850	1,867				1,867		(17)
Common dividends declared (per share: $0.04)	(10)	(10)				(10)
Repurchase of common stock	(110)	(110)					(110)
Other transactions impacting noncontrolling interest	(6)	(18)		(18)				12
Total Equity, end of period at Dec. 31, 2016	13,727	13,723	74	2,892	(1,382)	13,855	(1,716)	4
Redeemable Noncontrolling Interests
Other comprehensive income (loss)	(10)
Net income (loss)	(7)
Other transactions impacting noncontrolling interest	6
Ending Balance at Dec. 31, 2016	58
Increase (Decrease) In Stockholders Equity [Roll Forward]
Effect of issuing stock for employee benefit plans	248	248		51		(258)	455
Other comprehensive income (loss)	300	300			300
Net income (loss)	2,232	2,237				2,237		(5)
Common dividends declared (per share: $0.04)	(10)	(10)				(10)
Repurchase of common stock	(2,760)	(2,760)					(2,760)
Other transactions impacting noncontrolling interest	(2)	(3)		(3)				1
Total Equity, end of period at Dec. 31, 2017	13,735	$ 13,735	$ 74	$ 2,940	$ (1,082)	$ 15,824	$ (4,021)	$ 0
Redeemable Noncontrolling Interests
Other comprehensive income (loss)	(3)
Net income (loss)	0
Other transactions impacting noncontrolling interest	(6)
Ending Balance at Dec. 31, 2017	$ 49