Related Parties (Details) (Director [Member], USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Related Party Transaction [Line Items]
Related Party Transaction Amount of Assets Under Management in Defined Benefit Plans	$ 136.0
Amounts Invested in Defined Contribution Plan Mutual Fund Managed by a Directors Investment Advisory Firm	21.3
Amounts Invested in Defined Contribution Plan Mutual Fund Managed by a Directors Investment Advisory Firm Percentage of Total Defined Contribution Plan Investments	6.40%
Trinity [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	143.2
Related Party Transaction, Expenses from Transactions with Related Party	0.3	0.2
Pension Plan, Defined Benefit [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party	$ 0.2	$ 0.2