Derivative Financial Instruments - Schedule of Notional Amounts (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Total	$ 15,841.3	$ 10,735.4
Swaps
Derivative [Line Items]
Total	599.5	929.5
Futures, forwards and spot
Derivative [Line Items]
Total	3,017.1	3,249.9
Written options
Derivative [Line Items]
Total	6,393.9	3,688.8
Purchased options
Derivative [Line Items]
Total	$ 5,830.8	$ 2,867.2