Benefit Plans (Non-Qualified Retirement Plans) (Details) (Pension Plan, Defined Benefit, Non-qualified, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Pension Plan, Defined Benefit, Non-qualified
Non-Qualified Retirement Plans [Abstract]
Non-qualified retirement plan, number of years of highest average annual compensation used to determine benefits	5 years
Non-qualified retirement plan, number of years of employment used to determine benefits	10 years
Expected employer contributions in next fiscal year	$ 6.1
Future expected benefit payments, 2014	6.1
Future expected benefit payments, 2015	5.3
Future expected benefit payments, 2016	5.2
Future expected benefit payments, 2017	5.3
Future expected benefit payments, 2018	5.5
Future expected benefit payments, 2019 through 2023	$ 27.8