Capital Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		0 Months Ended	3 Months Ended	0 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Aug. 20, 2013 2013 Stock Repurchase Program	Mar. 31, 2014 2013 Stock Repurchase Program	Aug. 18, 2012 2012 Stock Repurchase Program	Mar. 31, 2014 2012 Stock Repurchase Program	Mar. 31, 2013 2012 Stock Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount			$ 250.0		$ 2.0
Shares repurchased (in shares)	100,000	100,000		1,300,000		0	500,000
Shares repurchased (in dollars)	1	1		50			14
Stock repurchase program, remaining authorized repurchase amount				$ 150
Stock repurchase program, remaining number of shares authorized to be repurchased						1,000,000