Derivative Instruments and Hedging Activities Schedule of Cash Flow Hedges in AOCI (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Total revenues	$ 1,384.3	$ 1,263.1	$ 1,203.3	$ 1,140.4	$ 1,128.8	$ 1,026.5	$ 1,045.0	$ 930.9	$ 4,991.1	$ 4,131.2	$ 3,551.1
Interest Expense									77.8	98.2	98.4
Product [Member]
Derivative [Line Items]
Total revenues									4,990.0	4,130.1	3,549.5
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Foreign Exchange Forward [Member]
Derivative [Line Items]
Total revenues									36.8	(1.8)	28.9
Interest Expense									0.0	0.0	0.0
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Total revenues									0.0	0.0	0.0
Interest Expense									$ (13.3)	$ (13.6)	$ 1.8