Earnings Per Share, Other Disclosures (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended		3 Months Ended		12 Months Ended						3 Months Ended	12 Months Ended
	Dec. 31, 2013	Apr. 30, 2013	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Warrant Transactions	Dec. 31, 2012 Warrant Transactions	Mar. 30, 2010 Warrant Transactions	Jun. 30, 2013 Common Stock	Dec. 31, 2013 Common Stock
Potential dilutive effect of options and Warrants
Options outstanding to purchase common shares	20,791		20,791		20,791	20,791
Average exercise price per share	$ 80.01		$ 80.01		$ 80.01	$ 80.01
Potential dilutive effect of shares underlying the options					0	0	0
Number of common shares underlying the Warrants outstanding								3,600,000	3,600,000	3,600,000
Average exercise price of common shares underlying warrants								61.08	61.31
Dividends
Payment of cash dividends to stockholders					$ 23.0	$ 19.6	$ 18.9
Payment of quarterly cash dividends			$ 0.30		$ 1.20	$ 1.00	$ 0.96
Cash dividend returned to the Company				0.6	0.6	0	0
Treasury Stock, Number of Shares and Restriction Disclosures [Abstract]
Shares returned from distribution of bankruptcy trust, shares											9,001	9,001
Repurchase of common shares authorized by Board	75.0	75.0
Repurchase of common shares pursuant to an authorization from the Board, shares					1,232,077	0	0					1,232,077
Weighted-average price of repurchases of common shares					$ 64.35
Repurchase of common shares pursuant to an authorization from the Board, value					79.3
Common shares available for additional share repurchase					$ 117.6	$ 46.9