Stockholders' Equity and Earnings Per Common Share Treasury Stock Transactions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Equity, Class of Treasury Stock
Number of Treasury Shares Repurchased	2.9	2.5	8.7	9.8
Cost of Shares Repurchased	$ 100.5	$ 75.0	$ 300.6	$ 268.5
Commission Paid on Common Stock Repurchased			0.1	0.1
Repurchase Program Authorized in July 2012
Equity, Class of Treasury Stock
Authorized Dollar Value of Treasury Share Repurchases Under Stock Repurchase Program	750.0		750.0
Remaining Dollar Value of Treasury Share Repurchases Authorized Under Share Repurchase Program	0		0
Repurchase Program Authorized in December 2013
Equity, Class of Treasury Stock
Authorized Dollar Value of Treasury Share Repurchases Under Stock Repurchase Program	750.0		750.0
Remaining Dollar Value of Treasury Share Repurchases Authorized Under Share Repurchase Program	$ 429.5		$ 429.5