Consolidated Statements of Equity (USD $) In Millions, except Share data, unless otherwise specified	Total USD ($)	Common Stock Shares	Common Stock Amount USD ($)	Accumulated Other Comprehensive Loss USD ($)	Retained Earnings USD ($)	Noncontrolling Interests' Equity USD ($)
Balance at Dec. 31, 2011			$ 836	$ (6)	$ 833	$ 3
Balance, shares at Dec. 31, 2011		75,362,956
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued pursuant to equity-based plans		193,316
Proceeds from issuance of shares pursuant to equity-based plans			1
Stock-based compensation			4	0	0	0
Dividends declared			0	0	(81)	0
Net income (loss)	140		0	0	141	(1)
Balance at Dec. 31, 2012			841	(6)	893	2
Balance, shares at Dec. 31, 2012		75,556,272
Issuances of common stock, net of issuance costs of $3		2,365,000
Issuances of common stock, net of issuance costs of $3			67
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued pursuant to equity-based plans		164,287
Proceeds from issuance of shares pursuant to equity-based plans			1
Stock-based compensation			2	0	0	0
Dividends declared			0	0	(85)	0
Net income (loss)	104		0	0	105	(1)
Other comprehensive income (loss)			0	1	0	0
Balance at Dec. 31, 2013	1,820		911	(5)	913	1
Balance, shares at Dec. 31, 2013		78,085,559
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued pursuant to equity-based plans		142,780
Proceeds from issuance of shares pursuant to equity-based plans			1
Stock-based compensation			6	0	0	0
Dividends declared			0	0	(88)	0
Net income (loss)	174		0	0	175	(1)
Other comprehensive income (loss)			0	(2)	0	0
Balance at Dec. 31, 2014	$ 1,911		$ 918	$ (7)	$ 1,000	$ 0
Balance, shares at Dec. 31, 2014		78,228,339