Advanced Technology Costs and Other Income (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2015
Research and Development [Abstract]
Other advanced technology costs		$ 4.7	$ 12.3	$ 18.5
Cost of Reimbursable Expense	$ 7.7
Increase in decontamination and decommissioning liability	$ 6.8