Capital Stock (Details Textual) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Aug. 24, 2015
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)	$ 1.04	$ 0.96	$ 0.84
Shares repurchased	772	536	810
Shares repurchased, value	$ 61	$ 40
2015 Stock Repurchase Program
Class of Stock [Line Items]
Authorized amount				$ 500
Shares repurchased	700	300
Shares repurchased, value	$ 50	$ 25
Remaining authorized repurchase amount	$ 288
Settlement of Employee Tax Withholding Obligations
Class of Stock [Line Items]
Shares repurchased	100	200
Shares repurchased, value	$ 11	$ 15