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 Income/(Loss)	Non- Controlling Interest in Consolidated Subsidiaries	Cumulative Effect, Period Of Adoption, Adjustment	Cumulative Effect, Period Of Adoption, Adjustment Retained Earnings
Beginning Balance (in shares) at Dec. 31, 2018		604,000,000	35,000,000
Beginning Balance at Dec. 31, 2018	$ 17,231	$ 6	$ (2,354)	$ 11,547	$ 8,317	$ (315)	$ 30
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	(33)					(33)
Exercise of common stock options (in shares)		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
Issuance under the employee stock purchase plan	28			28
Issuance of restricted stock (in shares)		2,000,000
Distributions of profits	(29)						(29)
Dividends paid to stockholders	(467)				(467)
Net income (loss) attributable to non-controlling interest	1				(22)		23
Net income	1,507				1,507
Ending Balance (in shares) at Sep. 30, 2019		607,000,000	49,000,000
Ending Balance at Sep. 30, 2019	17,185	$ 6	$ (3,538)	11,706	9,335	(348)	24
Redeemable non-controlling interest, Beginning balance at Dec. 31, 2018	71
Increase (Decrease) in Temporary Equity [Roll Forward]
Stock-based compensation	3
Net income (loss) attributable to non-controlling interest	(2)
Redeemable non-controlling interest, Ending balance at Sep. 30, 2019	72
Beginning Balance (in shares) at Dec. 31, 2018		604,000,000	35,000,000
Beginning Balance at Dec. 31, 2018	$ 17,231	$ 6	$ (2,354)	11,547	8,317	(315)	30
Ending Balance (in shares) at Dec. 31, 2019	607,000,000	607,000,000	53,000,000
Ending Balance at Dec. 31, 2019	$ 17,286	$ 6	$ (3,879)	11,742	9,629	(243)	31	$ (10)	$ (10)
Redeemable non-controlling interest, Beginning balance at Dec. 31, 2018	71
Redeemable non-controlling interest, Ending balance at Dec. 31, 2019	$ 78
Increase (Decrease) in Temporary Equity [Roll Forward]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
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
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
Issuance under the employee stock purchase plan	14			14
Distributions of profits	(15)						(15)
Dividends paid to stockholders	(155)				(155)
Net income (loss) attributable to non-controlling interest	0				(8)		8
Net income	537				537
Ending Balance (in shares) at Sep. 30, 2019		607,000,000	49,000,000
Ending Balance at Sep. 30, 2019	17,185	$ 6	$ (3,538)	11,706	9,335	(348)	24
Redeemable non-controlling interest, Beginning balance at Jun. 30, 2019	72
Increase (Decrease) in Temporary Equity [Roll Forward]
Stock-based compensation	1
Net income (loss) attributable to non-controlling interest	(1)
Redeemable non-controlling interest, Ending balance at Sep. 30, 2019	$ 72
Beginning Balance (in shares) at Dec. 31, 2019	607,000,000	607,000,000	53,000,000
Beginning Balance at Dec. 31, 2019	$ 17,286	$ 6	$ (3,879)	11,742	9,629	(243)	31	$ (10)	$ (10)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	(30)					(30)
Stock consideration issued for acquisition (in shares)		18,000,000
Stock consideration issued for acquisition	$ 1,895			1,895
Exercise of common stock options (in shares)	592,000	1,000,000
Exercise of common stock options	$ 26			26
Repurchases of common stock (in shares)			(14,000,000)
Repurchases of common stock	(1,247)		$ (1,247)
Payments relating to treasury shares	(72)		$ (72)
Stock-based compensation	105			105
Issuance under the employee stock purchase plan	33			33
Warrants issued to minority interest holders	3			3
Issuance of restricted stock (in shares)		2,000,000
Distributions of profits	(31)						(31)
Dividends paid to stockholders	(500)				(500)
Redeemable non-controlling interest	0
Issuance of non-controlling interest	9						9
Net income (loss) attributable to non-controlling interest	5				(17)		22
Net income	$ 1,580				1,580
Ending Balance (in shares) at Sep. 30, 2020	628,000,000	628,000,000	67,000,000
Ending Balance at Sep. 30, 2020	$ 19,052	$ 6	$ (5,198)	13,804	10,682	(273)	31
Redeemable non-controlling interest, Beginning balance at Dec. 31, 2019	78
Increase (Decrease) in Temporary Equity [Roll Forward]
Stock-based compensation	9
Warrants issued to minority interest holders	2
Redeemable non-controlling interest	10
Net income (loss) attributable to non-controlling interest	(5)
Redeemable non-controlling interest, Ending balance at Sep. 30, 2020	94
Beginning Balance (in shares) at Jun. 30, 2020		609,000,000	65,000,000
Beginning Balance at Jun. 30, 2020	16,994	$ 6	$ (5,050)	11,856	10,462	(321)	41
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	48					48
Stock consideration issued for acquisition (in shares)		18,000,000
Stock consideration issued for acquisition	1,895			1,895
Exercise of common stock options (in shares)		1,000,000
Exercise of common stock options	4			4
Repurchases of common stock (in shares)			(2,000,000)
Repurchases of common stock	(148)		$ (148)
Stock-based compensation	32			32
Issuance under the employee stock purchase plan	17			17
Distributions of profits	(16)						(16)
Dividends paid to stockholders	(170)				(170)
Net income (loss) attributable to non-controlling interest	2				(4)		6
Net income	$ 394				394
Ending Balance (in shares) at Sep. 30, 2020	628,000,000	628,000,000	67,000,000
Ending Balance at Sep. 30, 2020	$ 19,052	$ 6	$ (5,198)	$ 13,804	$ 10,682	$ (273)	$ 31
Redeemable non-controlling interest, Beginning balance at Jun. 30, 2020	95
Increase (Decrease) in Temporary Equity [Roll Forward]
Stock-based compensation	1
Net income (loss) attributable to non-controlling interest	(2)
Redeemable non-controlling interest, Ending balance at Sep. 30, 2020	$ 94