Earnings Per Share (Additional Disclosures) (Details) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Feb. 11, 2008	Feb. 15, 2013 Two Thousand Eight Notes [Member]	Dec. 31, 2012 Two Thousand Eight Notes [Member]	Jun. 25, 2012 Two Thousand Eight Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchased Face Amount			$ 5.2	$ 50.3	$ 15.0
Common stock included in share lending agreement	3,800,000	3,800,000