Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended	3 Months Ended								12 Months Ended
		Jan. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Repurchased In Period											239,495
Common Stock Repurchased - Amount	[1]										$ 32	$ 0	$ 34
Common Stock Repurchased - Shares Repurchased											2,100,000	0	1,700,000
Common Stock Repurchased - Weighted Average Cost Per Share											$ 15.33	$ 0.00	$ 19.37
Dividends, Common Stock											$ 133	$ 114	$ 87
Common Stock, Dividends, Per Share, Declared			$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.18	$ 0.18	$ 1.00	$ 0.86	$ 0.66
Common Stock, Shares, Issued			136,000,000				136,000,000				136,000,000	136,000,000
Common stock, shares outstanding			131,000,000				133,000,000				131,000,000	133,000,000
Treasury Stock, Shares			5,000,000								5,000,000
Common Stock, Capital Shares Reserved for Future Issuance			5,700,000								5,700,000
Preferred stock, shares authorized			10,000,000				10,000,000				10,000,000	10,000,000
Common Stock, Par or Stated Value Per Share			$ 0.10				$ 0.10				$ 0.10	$ 0.10	$ 0.10
Preferred Stock, Shares Issued			0				0				0	0
Preferred Stock, Shares Outstanding			0				0				0	0
Restricted Stock [Member]
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period											573,280
Restricted Stock Units (RSUs) [Member]
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period											322,168
Subsequent Event [Member]
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Common Stock Repurchased - Amount	[1]	$ 18
Common Stock Repurchased - Shares Repurchased		1,200,000
Common Stock Repurchased - Weighted Average Cost Per Share		$ 15.29

[1] (1) Additionally, in January 2016, we repurchased 1.2 million shares of our common stock at a weighted average cost of $15.29 per share for an aggregate amount of $18 million.