Consolidated Statements of Change in Equity, Accumulated Other Comprehensive Loss and Redeemable Non-Controlling Interest - USD ($) $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Non- Controlling Interest in Consolidated Subsidiaries	Redeemable Non-Controlling Interest
Beginning Balance (in shares) at Dec. 31, 2016		596,000,000	1,000,000
Beginning Balance at Dec. 31, 2016	$ 15,775	$ 6	$ (40)	$ 11,306	$ 4,810	$ (344)	$ 37	$ 36
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income	121					121
Exercise of common stock options	17			17
Repurchases of common stock (in shares)			(15,000,000)
Repurchases of common stock	(949)		$ (949)
Payments relating to treasury shares (in shares)			(1,000,000)
Payments relating to treasury shares	(88)		$ (88)
Stock-based compensation	152			152
Issuance of restricted stock (in shares)		4,000,000
Issuance of restricted stock	0		$ 1	(1)
Acquisition of non-controlling interest	(92)			(82)			(10)
Distributions of profits	(26)						(26)
Dividends paid to stockholders	(476)				(476)
Acquisition of redeemable non-controlling interest	(2)				(2)			(37)
Net income attributable to non-controlling interest	(1)				(28)		27	1
Net income	$ 2,554				2,554
Ending Balance (in shares) at Dec. 31, 2017	600,000,000	600,000,000	17,000,000
Ending Balance at Dec. 31, 2017	$ 16,985	$ 6	$ (1,076)	11,392	6,858	(223)	28	0
Accumulated other comprehensive loss was as follows:
Foreign currency translation adjustments	(136)
Comprehensive income from equity method investment	2
Employee benefit plans adjustments	(89)
Accumulated other comprehensive loss	(223)
Other comprehensive income	33					33
Exercise of common stock options	$ 4			4
Repurchases of common stock (in shares)	(4,105,013)		(4,000,000)
Repurchases of common stock	$ (300)		$ (300)
Payments relating to treasury shares (in shares)			(1,000,000)
Payments relating to treasury shares	(72)		$ (72)
Stock-based compensation	32			32
Issuance of restricted stock (in shares)		3,000,000
Issuance of restricted stock	0
Distributions of profits	(10)						(10)
Dividends paid to stockholders	(140)				(140)
Net income attributable to non-controlling interest	0				(10)		10	0
Net income	$ 474				474
Ending Balance (in shares) at Mar. 31, 2018	603,000,000	603,000,000	22,000,000
Ending Balance at Mar. 31, 2018	$ 17,006	$ 6	$ (1,448)	$ 11,428	$ 7,182	$ (190)	$ 28	$ 0
Accumulated other comprehensive loss was as follows:
Foreign currency translation adjustments	(103)
Comprehensive income from equity method investment	2
Employee benefit plans adjustments	(89)
Accumulated other comprehensive loss	$ (190)