Stockholders' Equity and Earnings Per Common Share Share Repurchases (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Repurchases of Common Shares [Abstract]
Number of Shares Repurchased	2.9	3.6	5.8	7.3
Cost of Shares Repurchased	$ 100.0	$ 98.4	$ 200.1	$ 193.5