Recent Accounting Guidance (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
New Accounting Pronouncement, Early Adoption [Line Items]
Decrease in total assets from early adoption	$ (5,898.9)	$ (6,170.7)
Decrease in total liabilities from early adoption	(4,794.6)	(5,058.7)
New Accounting Pronouncement, Early Adoption, Effect [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Decrease in total assets from early adoption	71.3	82.1
Decrease in total liabilities from early adoption	$ 71.3	$ 82.1