CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock, at Cost	Non-controlling Interests
Balance, shares at Dec. 31, 2019		133.0
Balance, value at Dec. 31, 2019	$ 5,687	$ 2	$ 2,722	$ 8,174	$ (39)	$ (5,218)	$ 46
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	105			99			6
Other comprehensive loss, net of taxes	(19)				(19)
Dividends declared	(76)			(76)
Distributions to noncontrolling interest partners	(6)						(6)
Issuance of common stock under benefit plans	6		3			3
Stock-based compensation expense	14		14
Exercise of stock options, shares		2.0
Exercise of stock options	80		12			$ 68
Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans	(13)		(13)
Purchases of treasury stock, shares		(1.0)				(0.7)
Purchases of treasury stock	(75)					$ (75)
Balance, shares at Mar. 31, 2020		134.0
Balance, value at Mar. 31, 2020	5,703	$ 2	2,738	8,197	(58)	(5,222)	46
Balance, Value at Dec. 31, 2019	76
Redeemable Non-controlling Interest [Abstract]
Net income	1
Distributions to noncontrolling interest partners	(1)
Balance, Value at Mar. 31, 2020	76
Balance, shares at Dec. 31, 2020		133.0
Balance, value at Dec. 31, 2020	6,809	$ 2	2,841	9,303	(21)	(5,366)	50
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	486			469			17
Other comprehensive loss, net of taxes	(10)				(10)
Dividends declared	(82)			(82)
Distributions to noncontrolling interest partners	(22)						(22)
Issuance of common stock under benefit plans	5		(29)			34
Stock-based compensation expense	18		18
Exercise of stock options, shares		1.0
Exercise of stock options	17		3			14
Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans	(21)		(9)			$ (12)
Purchases of treasury stock, shares		(3.0)				(3.4)
Purchases of treasury stock	(410)					$ (410)
Balance, shares at Mar. 31, 2021		131.0
Balance, value at Mar. 31, 2021	6,790	$ 2	$ 2,824	$ 9,690	$ (31)	$ (5,740)	$ 45
Balance, Value at Dec. 31, 2020	82
Redeemable Non-controlling Interest [Abstract]
Net income	4
Distributions to noncontrolling interest partners	(7)
Balance, Value at Mar. 31, 2021	$ 79