Capital Stock (Details Textual) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Aug. 24, 2015	Aug. 20, 2013	Aug. 18, 2012
Class of Stock [Line Items]
Common Stock, shares authorized	750,000,000	750,000,000
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Dividends declared per share (in usd per share)	$ 0.006196	$ 0.005632	$ 0.005120
Shares repurchased	95,000	5,203,000	3,483,000
Shares repurchased, value	$ 4	$ 179	$ 134
2015 Stock Repurchase Program
Class of Stock [Line Items]
Authorized amount				$ 500
Remaining authorized repurchase amount	$ 420
2013 Stock Repurchase Program
Class of Stock [Line Items]
Authorized amount					$ 250
Shares repurchased		2,000,000.0
Shares repurchased, value		$ 70
2012 Stock Repurchase Program
Class of Stock [Line Items]
Shares repurchased	0	800,000
Shares repurchased, value		$ 25
Remaining authorized repurchase shares	300,000
Remaining authorized repurchase amount	$ 12
Number of shares authorized to be repurchased						2,000,000.0
Settlement of Employee Tax Withholding Obligations
Class of Stock [Line Items]
Shares repurchased	100,000	100,000
Shares repurchased, value	$ 4	$ 4