Consolidated Statements of Changes in Equity 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, 2017		600,000,000	17,000,000
Beginning Balance at Dec. 31, 2017	$ 16,985	$ 6	$ (1,076)	$ 11,392	$ 6,858	$ (223)	$ 28	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	(42)					(42)
Exercise of common stock options	12			12
Repurchases of common stock (in shares)			(10,000,000)
Repurchases of common stock	(759)		$ (759)
Payments relating to treasury shares (in shares)			(2,000,000)
Payments relating to treasury shares	(76)		$ (76)
Stock-based compensation	73			73
Issuance of restricted stock (in shares)		3,000,000
Issuance of restricted stock	0
Distributions of profits	(10)						(10)
Dividends paid to stockholders	(279)				(279)
Net income attributable to non-controlling interest	0				(17)		17
Net income	936				936
Ending Balance (in shares) at Jun. 30, 2018		603,000,000	29,000,000
Ending Balance at Jun. 30, 2018	16,840	$ 6	$ (1,911)	11,477	7,498	(265)	35	0
Beginning Balance (in shares) at Mar. 31, 2018		603,000,000	22,000,000
Beginning Balance at Mar. 31, 2018	17,006	$ 6	$ (1,448)	11,428	7,182	(190)	28	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	(75)					(75)
Exercise of common stock options	8			8
Repurchases of common stock (in shares)			(6,000,000)
Repurchases of common stock	(459)		$ (459)
Payments relating to treasury shares (in shares)			(1,000,000)
Payments relating to treasury shares	(4)		$ (4)
Stock-based compensation	41			41
Dividends paid to stockholders	(139)				(139)
Net income attributable to non-controlling interest	0				(7)		7
Net income	462				462
Ending Balance (in shares) at Jun. 30, 2018		603,000,000	29,000,000
Ending Balance at Jun. 30, 2018	$ 16,840	$ 6	$ (1,911)	11,477	7,498	(265)	35	0
Beginning Balance (in shares) at Dec. 31, 2018	604,000,000	604,000,000	35,000,000
Beginning Balance at Dec. 31, 2018	$ 17,231	$ 6	$ (2,354)	11,547	8,317	(315)	30	71
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	6					6
Exercise of common stock options	17			17
Repurchases of common stock (in shares)			(10,000,000)
Repurchases of common stock	(780)		$ (780)
Payments relating to treasury shares	(60)		$ (60)
Stock-based compensation	73			73				2
Issuance under the employee stock purchase plan	14			14
Issuance of restricted stock (in shares)		2,000,000
Issuance of restricted stock	0
Distributions of profits	(14)						(14)
Dividends paid to stockholders	(312)				(312)
Net income attributable to non-controlling interest	1				(14)		15	(1)
Net income	$ 970				970
Ending Balance (in shares) at Jun. 30, 2019	606,000,000	606,000,000	45,000,000
Ending Balance at Jun. 30, 2019	$ 17,146	$ 6	$ (3,194)	11,651	8,961	(309)	31	72
Beginning Balance (in shares) at Mar. 31, 2019		606,000,000	41,000,000
Beginning Balance at Mar. 31, 2019	17,130	$ 6	$ (2,851)	11,597	8,644	(290)	24	71
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	(19)					(19)
Exercise of common stock options	12			12
Repurchases of common stock (in shares)			(4,000,000)
Repurchases of common stock	(340)		$ (340)
Payments relating to treasury shares	(3)		$ (3)
Stock-based compensation	40			40				2
Issuance under the employee stock purchase plan	2			2
Dividends paid to stockholders	(155)				(155)
Net income attributable to non-controlling interest	1				(6)		7	(1)
Net income	$ 478				478
Ending Balance (in shares) at Jun. 30, 2019	606,000,000	606,000,000	45,000,000
Ending Balance at Jun. 30, 2019	$ 17,146	$ 6	$ (3,194)	$ 11,651	$ 8,961	$ (309)	$ 31	$ 72