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)	(51)					(51)
Exercise of common stock options	19			19
Repurchases of common stock (in shares)			(14,000,000)
Repurchases of common stock	(1,059)		$ (1,059)
Payments relating to treasury shares (in shares)			(1,000,000)
Payments relating to treasury shares	(78)		$ (78)
Stock-based compensation	107			107
Issuance of restricted stock (in shares)		3,000,000
Issuance of restricted stock	0
Acquisition of non-controlling interest	(25)			(23)			(2)
Distributions of profits	(28)						(28)
Dividends paid to stockholders	(417)				(417)
Net income attributable to non-controlling interest	0				(24)		24
Net income	1,401				1,401
Ending Balance (in shares) at Sep. 30, 2018		603,000,000	32,000,000
Ending Balance at Sep. 30, 2018	16,854	$ 6	$ (2,213)	11,495	7,818	(274)	22	0
Beginning Balance (in shares) at Jun. 30, 2018		603,000,000	29,000,000
Beginning Balance at Jun. 30, 2018	16,840	$ 6	$ (1,911)	11,477	7,498	(265)	35	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	(9)					(9)
Exercise of common stock options	7			7
Repurchases of common stock (in shares)			(4,000,000)
Repurchases of common stock	(300)		$ (300)
Payments relating to treasury shares (in shares)			1,000,000
Payments relating to treasury shares	(2)		$ (2)
Stock-based compensation	34			34
Acquisition of non-controlling interest	(25)			(23)			(2)
Distributions of profits	(18)						(18)
Dividends paid to stockholders	(138)				(138)
Net income attributable to non-controlling interest	0				(7)		7
Net income	465				465
Ending Balance (in shares) at Sep. 30, 2018		603,000,000	32,000,000
Ending Balance at Sep. 30, 2018	$ 16,854	$ 6	$ (2,213)	11,495	7,818	(274)	22	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)	$ (33)					(33)
Exercise of common stock options (in shares)	575,000	1,000,000
Exercise of common stock options	$ 22			22
Repurchases of common stock (in shares)			(14,000,000)
Repurchases of common stock	(1,120)		$ (1,120)
Payments relating to treasury shares	(64)		$ (64)
Stock-based compensation	109			109				3
Issuance under the employee stock purchase plan	28			28
Issuance of restricted stock (in shares)		2,000,000
Issuance of restricted stock	0
Distributions of profits	(29)						(29)
Dividends paid to stockholders	(467)				(467)
Net income attributable to non-controlling interest	1				(22)		23	(2)
Net income	$ 1,507				1,507
Ending Balance (in shares) at Sep. 30, 2019	607,000,000	607,000,000	49,000,000
Ending Balance at Sep. 30, 2019	$ 17,185	$ 6	$ (3,538)	11,706	9,335	(348)	24	72
Beginning Balance (in shares) at Jun. 30, 2019		606,000,000	45,000,000
Beginning Balance at Jun. 30, 2019	17,146	$ 6	$ (3,194)	11,651	8,961	(309)	31	72
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	(39)					(39)
Exercise of common stock options (in shares)		1,000,000
Exercise of common stock options	5			5
Repurchases of common stock (in shares)			(4,000,000)
Repurchases of common stock	(340)		$ (340)
Payments relating to treasury shares	(4)		$ (4)
Stock-based compensation	36			36				1
Issuance under the employee stock purchase plan	14			14
Distributions of profits	(15)						(15)
Dividends paid to stockholders	(155)				(155)
Net income attributable to non-controlling interest	0				(8)		8	(1)
Net income	$ 537				537
Ending Balance (in shares) at Sep. 30, 2019	607,000,000	607,000,000	49,000,000
Ending Balance at Sep. 30, 2019	$ 17,185	$ 6	$ (3,538)	$ 11,706	$ 9,335	$ (348)	$ 24	$ 72