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
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)	25					25
Exercise of common stock options	5			5
Repurchases of common stock (in shares)			(6,000,000)
Repurchases of common stock	(440)		$ (440)
Payments relating to treasury shares	(57)		$ (57)
Stock-based compensation	33			33
Issuance under the employee stock purchase plan	12			12
Issuance of restricted stock (in shares)		2,000,000
Distributions of profits	(14)						(14)
Dividends paid to stockholders	(157)				(157)
Net income (loss) attributable to non-controlling interest	0				(8)		8
Net income	492				492
Ending Balance (in shares) at Mar. 31, 2019		606,000,000	41,000,000
Ending Balance at Mar. 31, 2019	17,130	$ 6	$ (2,851)	11,597	8,644	(290)	24
Redeemable non-controlling interest, Beginning balance at Dec. 31, 2018	71
Redeemable non-controlling interest, Ending balance at Mar. 31, 2019	$ 71
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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	(90)					(90)
Exercise of common stock options	11			11
Repurchases of common stock (in shares)			(8,000,000)
Repurchases of common stock	(699)		$ (699)
Payments relating to treasury shares	(69)		$ (69)
Stock-based compensation	38			38
Issuance under the employee stock purchase plan	16			16
Warrants issued to minority interest holders	3			3
Issuance of restricted stock (in shares)		2,000,000
Distributions of profits	(15)						(15)
Dividends paid to stockholders	(166)				(166)
Net income (loss) attributable to non-controlling interest	2				(8)		10
Net income	$ 658				658
Ending Balance (in shares) at Mar. 31, 2020	609,000,000	609,000,000	61,000,000
Ending Balance at Mar. 31, 2020	$ 16,965	$ 6	$ (4,647)	$ 11,810	$ 10,103	$ (333)	$ 26
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	(2)
Redeemable non-controlling interest, Ending balance at Mar. 31, 2020	$ 97