Capital Stock (Narrative) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Equity, Class of Treasury Stock [Line Items]
Shares authorized	800,000,000
Common stock stated value per share	$ 0.01
Common shares outstanding	184,734,000	211,877,000
Stock repurchased	28,000,000
Weighted-average cost per share repurchased	$ 55
Stock repurchase program, covenant percentage	1.00%
Preferred stock shares authorized	2,000,000
Preferred stock stated value per share	$ 1.00
Preferred stock, shares outstanding	0
Treasury stock, shares, acquired from employees	200,000
2007 Authorization [Member]
Equity, Class of Treasury Stock [Line Items]
Common stock repurchase authorization value	0
2014 Authorization [Member]
Equity, Class of Treasury Stock [Line Items]
Common stock repurchase authorization value	0
2015 Authorization [Member]
Equity, Class of Treasury Stock [Line Items]
Common stock repurchase authorization value	0