Consolidated Statements Of Equity - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Noncontrolling Interests
Beginning Balance, shares at Dec. 31, 2017		170,189
Beginning Balance at Dec. 31, 2017	$ 11,279	$ 2	$ 8,974	$ (249)	$ 2,547	$ 5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared ($0.32 per share)	(27)				(27)
Purchases of treasury stock, shares		(262)
Purchases of treasury stock	(45)			(45)
Stock-based compensation costs:
Vested compensation awards, shares		492
Issued awards, net	0	$ 0	0
Compensation costs included in net income	17		17			0
Net income	178				178	0
Ending Balance, shares at Mar. 31, 2018		170,419
Ending Balance at Mar. 31, 2018	11,402	$ 2	8,991	(294)	2,698	5
Beginning Balance, shares at Dec. 31, 2017		170,189
Beginning Balance at Dec. 31, 2017	11,279	$ 2	8,974	(249)	2,547	5
Ending Balance, shares at Dec. 31, 2018		169,499
Ending Balance at Dec. 31, 2018	12,111	$ 2	9,062	(423)	3,470	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared ($0.32 per share)	(54)				(54)
Exercise of long-term incentive stock options and employee stock purchases, shares		10
Exercise of long-term incentive stock options	0		0	0
Purchases of treasury stock, shares		(1,594)
Purchases of treasury stock	(222)			(222)
Stock-based compensation costs:
Vested compensation awards, shares		507
Issued awards, net	0	$ 0	0
Compensation costs included in net income	24		24			0
Net income	350				350	0
Ending Balance, shares at Mar. 31, 2019		168,422
Ending Balance at Mar. 31, 2019	$ 12,209	$ 2	$ 9,086	$ (645)	$ 3,766	$ 0