Condensed Consolidated Statements of Equity - USD ($) $ in Millions	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive Loss	Retained Earnings	Non-controlling Interests	Total
Balance at Dec. 31, 2017	$ 1	$ 1,138	$ (494)	$ (1,013)	$ 3,259	$ 26
Increase (Decrease) in Stockholders' Equity
Net income					140	3
Dividends declared					(44)	(3)
Share-based compensation, net of issuance		(6)	18
Other comprehensive income (loss)				41		(2)
Balance at Mar. 31, 2018	1	1,132	(476)	(972)	3,355	24
Balance at Dec. 31, 2017	1	1,138	(494)	(1,013)	3,259	26
Increase (Decrease) in Stockholders' Equity
Net income					349	8	$ 357
Dividends declared					(131)	(7)
Repurchases of common stock, net			(177)
Share-based compensation, net of issuance		(3)	21
Other comprehensive income (loss)				(111)		(4)
Other		(4)		(7)	7	(1)
Balance at Sep. 30, 2018	1	1,131	(650)	(1,131)	3,484	22
Balance at Mar. 31, 2018	1	1,132	(476)	(972)	3,355	24
Increase (Decrease) in Stockholders' Equity
Net income					114	2
Dividends declared					(44)	(1)
Repurchases of common stock, net			(141)
Share-based compensation, net of issuance			2
Other comprehensive income (loss)				(134)		(2)
Other		(4)			1	(1)
Balance at Jun. 30, 2018	1	1,128	(615)	(1,106)	3,426	22
Increase (Decrease) in Stockholders' Equity
Net income					95	3	98
Dividends declared					(43)	(3)
Repurchases of common stock, net			(36)
Share-based compensation, net of issuance		3	1
Other comprehensive income (loss)				(18)
Other				(7)	6
Balance at Sep. 30, 2018	1	1,131	(650)	(1,131)	3,484	22
Balance at Dec. 31, 2018	1	1,096	(1,091)	(1,154)	3,536	20	2,408
Increase (Decrease) in Stockholders' Equity
Net income					100	2
Dividends declared					(42)
Repurchases of common stock, net		32	31
Share-based compensation, net of issuance		9	10
Other comprehensive income (loss)				(6)
Balance at Mar. 31, 2019	1	1,137	(1,050)	(1,160)	3,594	22
Balance at Dec. 31, 2018	1	1,096	(1,091)	(1,154)	3,536	20	2,408
Increase (Decrease) in Stockholders' Equity
Net income					304	7	311
Dividends declared					(127)	(6)
Repurchases of common stock, net		32	31
Share-based compensation, net of issuance		9	16
Other comprehensive income (loss)				(60)		(2)
Balance at Sep. 30, 2019	1	1,137	(1,044)	(1,214)	3,713	19	2,612
Balance at Mar. 31, 2019	1	1,137	(1,050)	(1,160)	3,594	22
Increase (Decrease) in Stockholders' Equity
Net income					105	2
Dividends declared					(43)	(4)
Share-based compensation, net of issuance		1	3
Other comprehensive income (loss)				8		(4)
Balance at Jun. 30, 2019	1	1,138	(1,047)	(1,152)	3,656	16
Increase (Decrease) in Stockholders' Equity
Net income					99	3	102
Dividends declared					(42)	(2)
Share-based compensation, net of issuance		(1)	3
Other comprehensive income (loss)				(62)		2
Balance at Sep. 30, 2019	$ 1	$ 1,137	$ (1,044)	$ (1,214)	$ 3,713	$ 19	$ 2,612