Statement 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, 2015	$ 12,044	$ 12,035	$ 74	$ 2,859	$ (1,250)	$ 12,121	$ (1,769)	$ 9
Increase (Decrease) In Stockholders Equity [Roll Forward]
Effect of issuing stock for employee benefit plans	(15)	(15)		21		(89)	53
Other comprehensive income (loss)	262	262			262
Net income (loss)	515	519				519		(4)
Common dividends declared (per share: $0.04)	(10)	(10)				(10)
Repurchase of common stock	(110)	(110)					(110)
Other transactions impacting noncontrolling interest	(2)	(6)		(6)				4
Total Equity, end of period at Mar. 31, 2016	12,684	12,675	74	2,874	(988)	12,541	(1,826)	9
Beginning Balance at Dec. 31, 2015	69
Redeemable Noncontrolling Interests
Other comprehensive income (loss)	3
Net income (loss)	(1)
Other transactions impacting noncontrolling interest	2
Ending Balance at Mar. 31, 2016	73
Total Equity, beginning of period at Dec. 31, 2016	13,727	13,723	74	2,892	(1,382)	13,855	(1,716)	4
Increase (Decrease) In Stockholders Equity [Roll Forward]
Effect of issuing stock for employee benefit plans	38	38		23		(87)	102
Other comprehensive income (loss)	130	130			130
Net income (loss)	595	598				598		(3)
Common dividends declared (per share: $0.04)	(10)	(10)				(10)
Repurchase of common stock	(250)	(250)					(250)
Other transactions impacting noncontrolling interest	(1)	(3)		(3)				2
Total Equity, end of period at Mar. 31, 2017	14,229	$ 14,226	$ 74	$ 2,912	$ (1,252)	$ 14,356	$ (1,864)	$ 3
Beginning Balance at Dec. 31, 2016	58
Redeemable Noncontrolling Interests
Other comprehensive income (loss)	(2)
Net income (loss)	(2)
Other transactions impacting noncontrolling interest	2
Ending Balance at Mar. 31, 2017	$ 56