Derivative Financial Instruments and Hedging Activities Schedule of Fair Value by Balance Sheet Location (Details) - Not Designated as Hedging Instrument - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Derivative [Line Items]
Derivative Asset, Fair Value, Gross	$ 182.9	$ 114.9
Cash collateral	22.6	6.1
Derivative Asset, Fair Value, Gross, Total net of cash collateral	160.3	108.8
Derivative Liabilities, Fair Value, Gross	173.9	103.8
Cash collateral	34.8	25.6
Derivative Liabilities, Fair Value, Gross, Total net of cash collateral	139.1	78.2
Derivative Assets, Fair Value, Net	101.9	72.1
Derivative Assets, Total net of cash collateral	79.3	66.0
Derivative Liabilities, Fair Value, Net	92.9	60.9
Derivative Liabilities, Total net of cash collateral	$ 58.1	$ 35.3