Interest Income, Expense and Other Financing Costs (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Interest Income, Expense and Other Financing Costs
Interest income	[1]	$ 1.3	$ 1.2
Interest expense and other financing costs	[1]	(8.9)	(8.5)
Interest expense and other financing costs, net	[1]	$ (7.6)	$ (7.3)

[1] Amounts may not add due to rounding