Capital Stock (Details Textual) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 24, 2015	Aug. 18, 2012
Class of Stock [Line Items]
Common Stock, shares authorized	750,000	750,000
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Dividends declared per share (in usd per share)	$ 0.96	$ 0.84	$ 0.72
Shares repurchased	536	810	490
Shares repurchased, value	$ 40	$ 59
2015 Stock Repurchase Program
Class of Stock [Line Items]
Authorized amount				$ 500
Shares repurchased	300	700
Shares repurchased, value	$ 25	$ 50
Remaining authorized repurchase amount	$ 338
2012 Stock Repurchase Program
Class of Stock [Line Items]
Shares repurchased	300
Shares repurchased, value	$ 13
Number of shares authorized to be repurchased					2,000
Settlement of Employee Tax Withholding Obligations
Class of Stock [Line Items]
Shares repurchased	200	100
Shares repurchased, value	$ 15	$ 9