Derivative Financial Instruments and Hedging Activities Schedule of Notional Amounts (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Derivative [Line Items]
Notional amount	$ 16,160.4	$ 15,841.3
Swaps
Derivative [Line Items]
Notional amount	926.5	599.5
Futures, forwards and spot
Derivative [Line Items]
Notional amount	3,537.6	3,017.1
Written options
Derivative [Line Items]
Notional amount	6,051.6	6,393.9
Purchased options
Derivative [Line Items]
Notional amount	$ 5,644.7	$ 5,830.8