Employee Benefit Plans - Deferred Compensation Plans (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended		12 Months Ended
	Jan. 31, 2010	Feb. 28, 2009	Dec. 31, 2012 plans	Dec. 31, 2012 Deferred credits and other [Member]	Dec. 31, 2011 Deferred credits and other [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Other plans that contain deferred compensation assets			5
Deferred compensation liability				$ 82.8	$ 85.2
Company funded matching and discretionary contributions, Vesting Period		5 years
Deferred compensation expense	$ 5.6