Consolidated Statements Of Changes In Stockholders' Equity Statement - USD ($) $ in Millions	Total	Common Stock [Member]	Common Stock, Held in Treasury [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]
Beginning balances at Dec. 31, 2016	$ 3,892	$ 1	$ (319)	$ 551	$ 3,412	$ (121)	$ 368
Beginning balance, shares issued at Dec. 31, 2016		134,651,380
Beginning balance, Treasury shares at Dec. 31, 2016			5,726,377
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	304				291		13
Other comprehensive income (loss)	70					67	3
Shares issued—stock- based compensation (in shares)			(127,901)
Shares issued—stock- based compensation	(1)		$ (3)	(2)
Stock-based compensation, net of tax on stock options exercised	7			7
Dividends declared	(49)				(49)
Distributions to noncontrolling interests	(16)						(16)
Ending balances at Jun. 30, 2017	4,209	$ 1	$ (316)	556	3,654	(54)	368
Ending balance, shares issued at Jun. 30, 2017		134,651,380
Ending balance, Treasury shares at Jun. 30, 2017			5,598,476
Beginning balances at Dec. 31, 2017	5,369	$ 1	$ (302)	555	4,613	7	495
Beginning balance, shares issued at Dec. 31, 2017		134,651,380
Beginning balance, Treasury shares at Dec. 31, 2017			5,232,875
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	585				565		20
Other comprehensive income (loss)	(42)					(40)	(2)
Shares issued—stock- based compensation (in shares)			(233,110)
Shares issued—stock- based compensation	(8)		$ (13)	(5)
Stock-based compensation, net of tax on stock options exercised	8			8
Dividends declared	(54)				(54)
Distributions to noncontrolling interests	(29)						(29)
Ending balances at Jun. 30, 2018	5,846	$ 1	$ (289)	$ 558	5,125	$ (33)	$ 484
Ending balance, shares issued at Jun. 30, 2018		134,651,380
Ending balance, Treasury shares at Jun. 30, 2018			4,999,765
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting change	$ 1				$ 1