Condensed Consolidated Statements of Equity (Unaudited) - USD ($) $ in Millions	Total	Common Stock [member]	Additional Paid-in Capital [member]	Retained Earnings [member]	Accumulated Other Comprehensive Loss [member]	Net Parent Investment [Member]	Non-Controlling Interests [member]
Balance at Dec. 31, 2016	$ 3,823				$ (67)	$ 3,939	$ (49)
Net transfers to Parent	(9)					(9)
Issuance of common stock and reclassification of former Parent investment		$ 2	$ 3,928			(3,930)
Issuance of common stock and reclassification of former Parent investment (shares)		198,000,000
Share-based compensation, net	2		2
Net income (loss)	2,350			$ 2,350
Other comprehensive income (loss)	7				7
Dividends and dividend equivalents	(202)		(110)	(92)
Dividends and dividend equivalents (Shares)		16,000,000
Balance at Mar. 31, 2017	5,971	$ 2	3,820	2,258	(60)		(49)
Balance (shares) at Mar. 31, 2017		214,000,000
Balance at Dec. 31, 2016	3,823				(67)	$ 3,939	(49)
Net income (loss)	2,570
Other comprehensive income (loss)	22
Balance at Sep. 30, 2017	6,023	$ 2	3,827	2,286	(45)		(47)
Balance (shares) at Sep. 30, 2017		215,000,000
Balance at Mar. 31, 2017	5,971	$ 2	3,820	2,258	(60)		(49)
Balance (shares) at Mar. 31, 2017		214,000,000
Share-based compensation, net	3		3
Share-based compensation, net (Shares)		1,000,000
Net income (loss)	115			112			3
Other comprehensive income (loss)	7				7
Dividends and dividend equivalents	(93)			(93)
Distributions to noncontrolling interest	(2)						(2)
Balance at Jun. 30, 2017	6,001	$ 2	3,823	2,277	(53)		(48)
Balance (shares) at Jun. 30, 2017		215,000,000
Share-based compensation, net	4		4
Net income (loss)	105			103			2
Other comprehensive income (loss)	8				8
Dividends and dividend equivalents	(94)			(94)
Distributions to noncontrolling interest	(1)						(1)
Balance at Sep. 30, 2017	6,023	$ 2	3,827	2,286	(45)		(47)
Balance (shares) at Sep. 30, 2017		215,000,000
Balance at Dec. 31, 2017	$ 5,962	$ 2	3,825	2,229	(45)		(49)
Balance (shares) at Dec. 31, 2017	214,845,244	215,000,000
Share-based compensation, net	$ 3		3
Net income (loss)	149			150			(1)
Other comprehensive income (loss)	37				37
Dividends and dividend equivalents	(88)			(88)
Repurchase of common stock	(348)		(250)	(98)
Repurchases of common stock (Shares)		(14,000,000)
Balance at Mar. 31, 2018	5,715	$ 2	3,578	2,193	(8)		(50)
Balance (shares) at Mar. 31, 2018		201,000,000
Balance at Dec. 31, 2017	$ 5,962	$ 2	3,825	2,229	(45)		(49)
Balance (shares) at Dec. 31, 2017	214,845,244	215,000,000
Net income (loss)	$ 422
Other comprehensive income (loss)	36
Balance at Sep. 30, 2018	$ 5,728	$ 2	3,585	2,196	(9)		(46)
Balance (shares) at Sep. 30, 2018	201,168,698	201,000,000
Balance at Mar. 31, 2018	$ 5,715	$ 2	3,578	2,193	(8)		(50)
Balance (shares) at Mar. 31, 2018		201,000,000
Share-based compensation, net	3		3
Net income (loss)	218			216			2
Dividends and dividend equivalents	(178)			(178)
Distributions to noncontrolling interest	(1)						(1)
Balance at Jun. 30, 2018	5,757	$ 2	3,581	2,231	(8)		(49)
Balance (shares) at Jun. 30, 2018		201,000,000
Share-based compensation, net	4		4
Net income (loss)	55			52			3
Other comprehensive income (loss)	(1)				(1)
Dividends and dividend equivalents	(87)			(87)
Balance at Sep. 30, 2018	$ 5,728	$ 2	$ 3,585	$ 2,196	$ (9)		$ (46)
Balance (shares) at Sep. 30, 2018	201,168,698	201,000,000