Pension and Other Postretirement Benefit Plans Deferred Compensation Arrangements (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense	$ 1.3	$ 1.3	$ 1.2
Deferred Compensation Arrangement with Individual, Employer Contribution	$ 0.3	$ 0.3	$ 0.2