CONDENSED CONSOLIDATED STATEMENT OF CHANGES IN EQUITY - USD ($) shares in Thousands, $ 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, 2017	$ 6	$ 4,933	$ 8,588	$ 8	$ (7,516)	$ 23	$ 6,042
Beginning balance, shares at Dec. 31, 2017	630,282				(196,964)
Equity roll forward
Adoption of new accounting standards			85	(5)			80
Consolidated net income			1,394			(2)	1,392
Other comprehensive income (loss), net of tax				(19)			(19)
Cash dividends declared			(605)				(605)
Equity-based compensation transactions, net		34	2		$ 84		120
Equity-based compensation transaction, shares					2,181
Common stock repurchase program		(40)			$ (710)		(750)
Common stock repurchase program, shares					(8,375)
Divestiture of noncontrolling interest						(19)	(19)
Other, net, shares					1
Ending balance at Sep. 30, 2018	$ 6	4,927	9,464	(16)	$ (8,142)	2	6,241
Ending balance, shares at Sep. 30, 2018	630,282				(203,157)
Beginning balance at Jun. 30, 2018	$ 6	4,935	9,166	(49)	$ (8,004)	2	6,056
Beginning balance, shares at Jun. 30, 2018	630,282				(201,906)
Equity roll forward
Consolidated net income			499			(1)	498
Other comprehensive income (loss), net of tax				33			33
Cash dividends declared			(199)				(199)
Equity-based compensation transactions, net		32	(2)		$ 22		52
Equity-based compensation transaction, shares					557
Common stock repurchase program		(40)			$ (160)		(200)
Common stock repurchase program, shares					(1,807)
Other, net						1	1
Other, net, shares					(1)
Ending balance at Sep. 30, 2018	$ 6	4,927	9,464	(16)	$ (8,142)	2	6,241
Ending balance, shares at Sep. 30, 2018	630,282				(203,157)
Beginning balance at Dec. 31, 2018	$ 6	4,993	9,797	(87)	$ (8,434)	1	6,276
Beginning balance, shares at Dec. 31, 2018	630,282				(206,299)
Equity roll forward
Consolidated net income			1,223			1	1,224
Other comprehensive income (loss), net of tax				54			54
Cash dividends declared			(658)				(658)
Equity-based compensation transactions, net		33	2		$ 100		135
Equity-based compensation transaction, shares					2,421
Common stock repurchase program					$ (244)		(244)
Common stock repurchase program, shares					(2,247)
Other, net, shares					3
Ending balance at Sep. 30, 2019	$ 6	5,026	10,364	(33)	$ (8,578)	2	6,787
Ending balance, shares at Sep. 30, 2019	630,282				(206,122)
Beginning balance at Jun. 30, 2019	$ 6	4,962	10,088	(22)	$ (8,568)	1	6,467
Beginning balance, shares at Jun. 30, 2019	630,282				(206,482)
Equity roll forward
Consolidated net income			495				495
Other comprehensive income (loss), net of tax				(11)			(11)
Cash dividends declared			(218)				(218)
Equity-based compensation transactions, net		28	(1)		$ 26		53
Equity-based compensation transaction, shares					613
Common stock repurchase program		36			$ (36)
Common stock repurchase program, shares					(254)
Other, net						1	1
Other, net, shares					1
Ending balance at Sep. 30, 2019	$ 6	$ 5,026	$ 10,364	$ (33)	$ (8,578)	$ 2	$ 6,787
Ending balance, shares at Sep. 30, 2019	630,282				(206,122)