CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Millions	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]	Noncontrolling Interests [Member]	Total
Beginning balance at Dec. 31, 2014	$ 6	$ 4,585	$ 6,888	$ 23	$ (5,636)	$ 23	$ 5,889
Beginning balance, shares at Dec. 31, 2014	630,282				(171,745)
Equity roll forward
Consolidated net income			753			(1)	752
Other comprehensive income (loss), net of tax				(150)			(150)
Cash dividends			(695)				(695)
Equity-based compensation transactions, net of tax		62	(7)		$ 116		171
Equity-based compensation transaction, shares					3,457
Common stock repurchase program		180			$ (780)		$ (600)
Common stock repurchase program, shares					(14,823)		(14,823,000)
Other, net, shares					6
Ending balance at Dec. 31, 2015	$ 6	4,827	6,939	(127)	$ (6,300)	22	$ 5,367
Ending balance, shares at Dec. 31, 2015	630,282				(183,105)
Equity roll forward
Consolidated net income			1,182			(2)	1,180
Other comprehensive income (loss), net of tax				47			47
Cash dividends			(726)				(726)
Equity-based compensation transactions, net of tax		69	(7)		$ 124		186
Equity-based compensation transaction, shares					3,556
Common stock repurchase program		(45)			$ (680)		$ (725)
Common stock repurchase program, shares					(11,241)		(11,241,000)
Other, net		(1)			$ (11)	3	$ (9)
Other, net, shares					(177)
Ending balance at Dec. 31, 2016	$ 6	4,850	7,388	(80)	$ (6,867)	23	5,320
Ending balance, shares at Dec. 31, 2016	630,282				(190,967)
Equity roll forward
Consolidated net income			1,949				1,949
Other comprehensive income (loss), net of tax				88			88
Cash dividends			(750)				(750)
Equity-based compensation transactions, net of tax		38	1		$ 146		185
Equity-based compensation transaction, shares					4,064
Common stock repurchase program		45			$ (795)		$ (750)
Common stock repurchase program, shares					(10,058)		(10,058,000)
Other, net, shares					(3)
Ending balance at Dec. 31, 2017	$ 6	$ 4,933	$ 8,588	$ 8	$ (7,516)	$ 23	$ 6,042
Ending balance, shares at Dec. 31, 2017	630,282				(196,964)