CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock, at Cost	Non-controlling Interests
Balance, value at Dec. 31, 2012	$ 4,186	$ 2	$ 2,371	$ 4,690	$ 14	$ (2,914)	$ 23
Balance, shares at Dec. 31, 2012		158.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	883			849			34
Other comprehensive loss, net of tax	(22)				(22)
Dividends declared	(181)			(181)
Distributions to noncontrolling interests	(32)						(32)
Issuance of common stock under benefit plans, value	20		3			17
Issuance of common stock under benefit plans, shares		1.0
Stock-based compensation expense	28		24			4
Exercise of stock options, value	138		(9)			147
Exercise of stock options, shares		3.0
Tax benefits associated with stock-based compensation plans	1		1
Shares to cover employee payroll tax withholdings on stock issued under benefit plans, value	(11)		(11)
Shares to cover employee payroll tax withholdings on stock issued under benefit plans, shares		(1.0)
Purchases of treasury stock, value	(1,037)					(1,037)
Purchases of treasury stock, shares		(17.0)
Balance, value at Dec. 31, 2013	3,973	$ 2	2,379	5,358	(8)	(3,783)	25
Balance, shares at Dec. 31, 2013		144.0
Balance, value at Dec. 31, 2012	0
Balance, value at Dec. 31, 2013	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	592			556			36
Other comprehensive loss, net of tax	(19)				(19)
Dividends declared	(191)			(191)
Distributions to noncontrolling interests	(31)						(31)
Issuance of common stock under benefit plans, value	19		2			17
Issuance of common stock under benefit plans, shares		1.0
Stock-based compensation expense	51		48			3
Exercise of stock options, value	78		(2)			80
Exercise of stock options, shares		1.0
Tax benefits associated with stock-based compensation plans	(3)		(3)
Shares to cover employee payroll tax withholdings on stock issued under benefit plans, value	(6)		(6)
Purchases of treasury stock, value	(132)					(132)
Purchases of treasury stock, shares		(2.0)
Other	(1)						(1)
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
Balance, value at Dec. 31, 2014	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	753
Net income	751			709			42
Other comprehensive 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	1.1	1.0
Tax benefits associated with stock-based compensation plans	$ 5		$ 5
Shares to cover employee payroll tax withholdings on stock issued under benefit plans, value	(7)		(7)
Purchases of treasury stock, value	(224)					(224)
Purchases of treasury stock, shares		(3.0)
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
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