Schedule of Stockholders Equity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 40	$ 34	$ 145	$ 132
Common Stock, Shares, Outstanding beginning of period			88,946,704
Issuance of shares pursuant to equity-based plans			$ 1	1
Adjustments Related to Tax Withholding for Share-based Compensation			2	2
Stockholders' Equity			2,344	2,258
Dividends declared			(90)	(84)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent				1
Net Income			$ 145	132
Common Stock, Shares, Outstanding end of period	89,091,955		89,091,955
Stockholders' Equity	$ 2,402	$ 2,310	$ 2,402	$ 2,310
Common Stock [Member]
Common Stock, Shares, Outstanding beginning of period			88,946,704	88,792,751
Issuances of shares pursuant to equity-based plans			145,251	133,875
Common Stock, Shares, Outstanding end of period	89,091,955	88,926,626	89,091,955	88,926,626
Common Stock Including Additional Paid in Capital [Member]
Issuance of shares pursuant to equity-based plans			$ 1	$ 1
Adjustments Related to Tax Withholding for Share-based Compensation			2	2
Stockholders' Equity			1,201	1,196
Dividends declared			0	0
Stockholders' Equity	$ 1,204	$ 1,199	1,204	1,199
AOCI Attributable to Parent [Member]
Stockholders' Equity			(7)	(8)
Stock-based compensation			0	0
Dividends declared			0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent				1
Stockholders' Equity	(7)	(7)	(7)	(7)
Retained Earnings [Member]
Stockholders' Equity			1,150	1,070
Stock-based compensation			0	0
Dividends declared			(90)	(84)
Net Income				132
Stockholders' Equity	$ 1,205	$ 1,118	$ 1,205	$ 1,118