Derivatives - Gains/(Losses) from Hedging Activities (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Gains/(Losses) from Derivatives
Revenues	$ 1,114.7	$ 1,340.5	$ 2,304.7	$ 2,677.5
Interest expense	(29.3)	(38.6)	(62.2)	(78.3)
Fair Value Hedges \| Interest rate contracts \| Interest Expense
Cash Flow and Fair Value Hedges
Hedged items		(0.6)		(0.9)
Derivatives designated as hedging instruments		0.6		1.0
Cash Flow Hedges \| Foreign currency contracts \| Revenue
Cash Flow and Fair Value Hedges
Gains/(losses) reclassified from AOCL into earnings	4.2	2.1	10.8	3.5
Amount excluded from effectiveness testing recognized in earnings based on an amortization approach	2.8	2.8	6.3	5.1
Amount excluded from effectiveness testing recognized in earnings based on changes in fair value		$ 1.0		$ 2.3
Cash Flow Hedges \| Interest rate contracts \| Interest Expense
Cash Flow and Fair Value Hedges
Gains/(losses) reclassified from AOCL into earnings	$ (0.1)		$ (0.3)

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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