Investments (Details 1) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Mar. 01, 2013	Dec. 31, 2012
Investments, Debt and Equity Securities [Abstract]
Annual Funding Obligation		$ 50.4
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	28.3		15.0
Available-for-sale Securities, Fair Value Disclosure	30.9		17.8
Cash And Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	6.3		1.3
Available-for-sale Securities, Fair Value Disclosure	6.3		1.3
U.S. Equity Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	8.1		5.4
Available-for-sale Securities, Fair Value Disclosure	10.1		7.4
International Equity Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	4.2		3.4
Available-for-sale Securities, Fair Value Disclosure	4.7		3.8
Municipal Bond Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	9.7		4.9
Available-for-sale Securities, Fair Value Disclosure	$ 9.8		$ 5.3