Equity Investments (Summary Of Investment In Joint Venture, Balance Sheet Data) (Details) - WAVE [Member] - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Current assets	$ 113.1	$ 118.7
Noncurrent assets	50.3	52.1
Current liabilities	40.7	23.3
Other noncurrent liabilities	$ 244.6	$ 248.9