Schedule of Stockholders Equity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ 0		$ 0
Payments of Stock Issuance Costs				$ 12
Stock Issued During Period, Shares, New Issues				10,400,000
Proceeds from Issuance of Common Stock			$ 0	$ 271
Common Stock, Shares, Outstanding beginning of period			88,792,751
Stockholders' Equity			$ 2,258
Common Stock, Shares, Outstanding end of period	88,926,626		88,926,626
Stockholders' Equity	$ 2,310		$ 2,310
Common Stock [Member]
Common Stock, Shares, Outstanding beginning of period			88,792,751	78,228,339
Issuances of shares pursuant to equity-based plans			133,875	143,833
Common Stock, Shares, Outstanding end of period	88,926,626	88,772,172	88,926,626	88,772,172
Common Stock Including Additional Paid in Capital [Member]
Proceeds from Issuance of Common Stock				$ 271
Issuance of shares pursuant to equity-based plans			$ 1	1
Adjustments Related to Tax Withholding for Share-based Compensation			2	3
Stockholders' Equity			1,196	918
Dividends declared			0	0
Stockholders' Equity	$ 1,199	$ 1,193	1,199	1,193
AOCI Attributable to Parent [Member]
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent			(1)
Stockholders' Equity			(8)	(7)
Stock-based compensation			0	0
Dividends declared			0	0
Stockholders' Equity	(7)	(7)	(7)	(7)
Retained Earnings [Member]
Stockholders' Equity			1,070	1,000
Stock-based compensation			0	0
Dividends declared			(84)	(75)
Net Income			132	121
Stockholders' Equity	1,118	1,046	1,118	1,046
Stockholders' Equity, Total [Member]
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent			1
Proceeds from Issuance of Common Stock				271
Issuance of shares pursuant to equity-based plans			1	1
Adjustments Related to Tax Withholding for Share-based Compensation			2	3
Stockholders' Equity			2,258	1,911
Dividends declared			(84)	(75)
Net Income			132	121
Stockholders' Equity	$ 2,310	$ 2,232	$ 2,310	$ 2,232