Guarantees and Indemnifications (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014
Guarantee Of Financial Obligations Of Npt [Member]
Guarantee Obligations [Line Items]
Guarantee Obligations Maximum Exposure	$ 25.0
Various Subsidiary Surety Bonds And Performance Guarantees Expiring Between 2014 And 2016 [Member]
Guarantee Obligations [Line Items]
Guarantee Obligations Maximum Exposure	67.0
Guarantee Of Rocky River Reality And Nusco Lease Payments For Real Estate And Vehicles Expiring 2019 Through 2024 [Member]
Guarantee Obligations [Line Items]
Guarantee Obligations Maximum Exposure	16.0
Guarantee Of Debt Of Ne Hydros [Member]
Guarantee Obligations [Line Items]
Guarantee Obligations Maximum Exposure	$ 2.5