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, value at Dec. 31, 2016	$ 4,660	$ 2	$ 2,545	$ 6,613	$ (72)	$ (4,460)	$ 32
Balance, shares at Dec. 31, 2016		137.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	817			772			45
Other comprehensive income (loss), net of tax	24				24
Dividends declared	(247)			(247)
Distributions to noncontrolling interest partners	(47)						(47)
Issuance of common stock under benefit plans	23		11			12
Stock-based compensation expense	79		75			4
Exercise of stock options, value	130		4			126
Exercise of stock options, shares		3.0
Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans	(23)		(23)
Purchases of treasury stock, value	(465)					$ (465)
Purchases of treasury stock, shares		(5.0)				(4.6)
Contributions from noncontrolling interest partners	4						4
Balance, value at Dec. 31, 2017	4,955	$ 2	2,612	7,138	(48)	$ (4,783)	34
Balance, shares at Dec. 31, 2017		135.0
Balance, value at Dec. 31, 2016	77
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income	7
Distributions to noncontrolling interest partners	(4)
Balance, value at Dec. 31, 2017	80
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	781			736			45
Other comprehensive income (loss), net of tax	(9)				(9)
Dividends declared	(274)			(274)
Distributions to noncontrolling interest partners	(44)						(44)
Issuance of common stock under benefit plans	28		14			14
Stock-based compensation expense	61		56			5
Exercise of stock options, value	99		6			93
Exercise of stock options, shares		3.0
Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans	(21)		(21)
Purchases of treasury stock, value	(325)					$ (325)
Purchases of treasury stock, shares		(3.0)				(3.4)
Contributions from noncontrolling interest partners	16						16
Reclassification of stranded tax effects resulting from enactment of the Tax Cuts and Jobs Act	0			2	(2)
Balance, value at Dec. 31, 2018	5,267	$ 2	2,667	7,602	(59)	$ (4,996)	51
Balance, shares at Dec. 31, 2018		135.0
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income	7
Distributions to noncontrolling interest partners	(10)
Balance, value at Dec. 31, 2018	77
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	900			858			42
Other comprehensive income (loss), net of tax	20				20
Dividends declared	(286)			(286)
Distributions to noncontrolling interest partners	(47)						(47)
Issuance of common stock under benefit plans	24		9			15
Stock-based compensation expense	56		55			1
Exercise of stock options, value	119		7			112
Exercise of stock options, shares		2.0
Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans	(16)		(16)
Purchases of treasury stock, value	(350)					$ (350)
Purchases of treasury stock, shares		(4.0)				(3.5)
Balance, value at Dec. 31, 2019	5,687	$ 2	$ 2,722	$ 8,174	$ (39)	$ (5,218)	$ 46
Balance, shares at Dec. 31, 2019		133.0
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income	6
Distributions to noncontrolling interest partners	(7)
Balance, value at Dec. 31, 2019	$ 76