Schedule of Equity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Payments of Stock Issuance Costs			$ 12
Proceeds from Issuance of Common Stock			$ 271	$ 0
Common Stock, Shares, Outstanding beginning of period			78,228,339
Stockholders' Equity			$ 1,911
Net Income	$ 36	$ 39	$ 121	$ 132
Common Stock, Shares, Outstanding end of period	88,772,172		88,772,172
Stockholders' Equity	$ 2,232		$ 2,232
Common Stock [Member]
Stock Issued During Period, Shares, New Issues			10,400,000
Common Stock, Shares, Outstanding beginning of period			78,228,339	78,085,559
Issuances of shares pursuant to equity-based plans			143,833	123,869
Common Stock, Shares, Outstanding end of period	88,772,172	78,209,428	88,772,172	78,209,428
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			3
Stockholders' Equity			918	911
Stock-based compensation				4
Dividends declared			0	0
Stockholders' Equity	$ 1,193	$ 916	1,193	916
AOCI Attributable to Parent [Member]
Stockholders' Equity			(7)	(5)
Stock-based compensation			0	0
Dividends declared			0	0
Stockholders' Equity	(7)	(5)	(7)	(5)
Retained Earnings [Member]
Stockholders' Equity			1,000	913
Stock-based compensation			0	0
Dividends declared			(75)	(67)
Net Income			121	132
Stockholders' Equity	1,046	978	1,046	978
Stockholders' Equity, Total [Member]
Proceeds from Issuance of Common Stock			271
Issuance of shares pursuant to equity-based plans			1	1
Stockholders' Equity			1,911	1,819
Stock-based compensation			3	4
Dividends declared			(75)	(67)
Net Income			121	132
Stockholders' Equity	$ 2,232	$ 1,889	$ 2,232	$ 1,889