Schedule of Stockholders Equity (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Common Stock, Shares, Outstanding beginning of period		89,267,959			89,267,959
Issuance of shares pursuant to equity-based plans	$ 1	$ 0	$ 0	$ 0
Adjustments Related to Tax Withholding for Share-based Compensation	2		2
Stockholders' Equity	2,548	2,506	2,449	2,416	$ 2,506	$ 2,416
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	1	1	46
Dividends declared	(35)	(32)	(32)	(30)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	25	73	46	64	98	110
Reclassification of stranded tax effects due to Tax Reform		0			(2)
Stockholders' Equity	$ 2,542	$ 2,548	$ 2,465	$ 2,449	$ 2,542	$ 2,465
Common Stock [Member]
Common Stock, Shares, Outstanding beginning of period	89,356,311	89,267,959	89,214,119	89,114,265	89,267,959	89,114,265
Issuances of shares pursuant to equity-based plans	15,249	88,352	24,087	99,854
Common Stock, Shares, Outstanding end of period	89,371,560	89,356,311	89,238,206	89,214,119	89,371,560	89,238,206
Common Stock Including Additional Paid in Capital [Member]
Issuance of shares pursuant to equity-based plans	$ 1	$ 0	$ 0	$ 0
Adjustments Related to Tax Withholding for Share-based Compensation	2		2	(1)
Stockholders' Equity	1,212	1,212	1,206	1,207	$ 1,212	$ 1,207
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0
Dividends declared		0	0	0
Stockholders' Equity	1,215	1,212	1,208	1,206	1,215	1,208
AOCI Attributable to Parent [Member]
Stockholders' Equity	(8)	(7)	(8)	(8)	(7)	(8)
Stock-based compensation			0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	1	1	0
Dividends declared	0	0	0	0
Reclassification of stranded tax effects due to Tax Reform		(2)
Stockholders' Equity	(7)	(8)	(8)	(8)	(7)	(8)
Retained Earnings [Member]
Stockholders' Equity	1,344	1,301	1,251	1,217	1,301	1,217
Stock-based compensation	0		0	0
Dividends declared	35	32	32	30
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest			46	64
Reclassification of stranded tax effects due to Tax Reform		(2)
Stockholders' Equity	$ 1,334	$ 1,344	$ 1,265	$ 1,251	$ 1,334	$ 1,265