Capital Stock (Changes in Common Stock Outstanding) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in Common Stock Outstanding [Roll Forward]
Beginning Balance, January 1	178,377	182,300	184,557
Stock incentive plan net activity	1,085	1,280	1,226
Repurchase of common stock	(95)	(5,203)	(3,483)
Ending Balance, December 31	179,367	178,377	182,300