Stockholders' Equity and Earnings Per Common Share Share Repurchases (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Share Repurchase Table [Line Items]
Treasury Stock, Shares, Acquired	2.5	5.1	9.8	18.6	23.6
Treasury Stock, Value, Acquired, Cost Method	$ 75.0	$ 100.2	$ 268.5	$ 400.5	$ 500.6