Schedule of Stockholders Equity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Common Stock, Shares, Outstanding beginning of period			89,114,265
Issuance of shares pursuant to equity-based plans			$ 0	$ 1
Adjustments Related to Tax Withholding for Share-based Compensation			2	2
Stockholders' Equity			2,416	2,344
Dividends declared			(95)	(90)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 53	$ 40	$ 163	145
Common Stock, Shares, Outstanding end of period	89,244,659		89,244,659
Stockholders' Equity	$ 2,486	$ 2,402	$ 2,486	$ 2,402
Common Stock [Member]
Common Stock, Shares, Outstanding beginning of period			89,114,265	88,946,704
Issuances of shares pursuant to equity-based plans			130,394	145,251
Common Stock, Shares, Outstanding end of period	89,244,659	89,091,955	89,244,659	89,091,955
Common Stock Including Additional Paid in Capital [Member]
Issuance of shares pursuant to equity-based plans			$ 0	$ 1
Adjustments Related to Tax Withholding for Share-based Compensation			2	2
Stockholders' Equity			1,207	1,201
Dividends declared			0	0
Stockholders' Equity	$ 1,209	$ 1,204	1,209	1,204
AOCI Attributable to Parent [Member]
Stockholders' Equity			(8)	(7)
Stock-based compensation			0	0
Dividends declared			0	0
Stockholders' Equity	(8)	(7)	(8)	(7)
Retained Earnings [Member]
Stockholders' Equity			1,217	1,150
Stock-based compensation			0	0
Dividends declared			(95)	(90)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest			163	145
Stockholders' Equity	$ 1,285	$ 1,205	$ 1,285	$ 1,205