Change in Financial Statement due to adoption of Policy (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Item Effected [Line Items]
Long-term debt	$ 3,428.6	$ 3,380.6
Other assets	162.8	140.4
As Previously Reported [Member]
Item Effected [Line Items]
Long-term debt		3,401.0
Other assets		160.8
Reclassification [Member]
Item Effected [Line Items]
Long-term debt	19.9	(20.4)
Other assets	19.9	$ (20.4)
Previous Accounting Guidance [Member]
Item Effected [Line Items]
Long-term debt	3,448.5
Other assets	$ 182.7