Common Stock Purchase Programs Common Stock Purchase Programs Narrative (Details) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2012
Equity [Abstract]
Share Repurchase Program, Original Authorization, Date	1995
Stock Repurchase Program, Authorized Amount	8,000,000
Common Shares Purchased and Retired Under Repurchase Program, Total	4,800,000
Shares Purchased Under Repurchase Program, Total Value	$ 130.9
Shares Repurchased Under Repurchase Program, Average Value Per Share	$ 27.16
Share Repurchase Program March 2000 Authorization, Number of Shares	4,000,000
Share Repurchase Program, March 2000 Authorization, Total Shares Repurchased	818,000
Share Repurchase Program, March 2000 Authorization, Total Share Repurchase Value	$ 26.9
Share Repurchase Program, March 2000 Authorization, Shares Repurchased Average Value Per Share	$ 32.82
Share Repurchase Program, Latest Repurchase, Date	2005
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased	3,200,000