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, 2014	$ 4,330	$ 2	$ 2,418	$ 5,723	$ (27)	$ (3,815)	$ 29
Balance, shares at Dec. 31, 2014		144.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	751			709			42
Other comprehensive income (loss), net of tax	(11)				(11)
Dividends declared	(219)			(219)
Distributions to noncontrolling interests	(42)						(42)
Issuance of common stock under benefit plans, value	21		6			15
Issuance of common stock under benefit plans, shares		1.0
Stock-based compensation expense	52		48			4
Exercise of stock options, value	60					60
Exercise of stock options, shares		1.0
Tax benefits associated with stock-based compensation plans	5		5
Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans, value	(7)		(7)
Purchases of treasury stock, value	(224)					$ (224)
Purchases of treasury stock, shares		(3.0)				(3.2)
Sale of redeemable noncontrolling interest	11		11
Adjustment to fair value	(14)			(14)
Balance, value at Dec. 31, 2015	4,713	$ 2	2,481	6,199	(38)	$ (3,960)	29
Balance, shares at Dec. 31, 2015		143.0
Balance, value at Dec. 31, 2014	0
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income	2
Sale of redeemable noncontrolling interest	54
Adjustment to fair value	14
Balance, value at Dec. 31, 2015	70
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	689			645			44
Other comprehensive income (loss), net of tax	(34)				(34)
Dividends declared	(231)			(231)
Distributions to noncontrolling interests	(41)						(41)
Issuance of common stock under benefit plans, value	22		7			15
Stock-based compensation expense	69		65			4
Exercise of stock options, value	73		2			71
Exercise of stock options, shares		1.0
Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans, value	(10)		(10)
Purchases of treasury stock, value	(590)					$ (590)
Purchases of treasury stock, shares		(7.0)				(7.4)
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 Temporary Equity [Roll Forward]
Net income	7
Balance, value at Dec. 31, 2016	77
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 interests	(47)						(47)
Issuance of common stock under benefit plans, value	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, value	(23)		(23)
Purchases of treasury stock, value	(465)					$ (465)
Purchases of treasury stock, shares		(5.0)				(4.6)
Sale of redeemable noncontrolling interest	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
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income	7
Distributions to noncontrolling interests	(4)
Balance, value at Dec. 31, 2017	$ 80