Fair Value Measurements and the Fair Value Option - Derivatives Financial Instruments (Details) € in Millions, £ in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2020 GBP (£)	Mar. 31, 2020 EUR (€)	Dec. 31, 2019 USD ($)
Derivative [Line Items]
Unrealized (losses) gains, arising during the period	$ 3.4
Hedge Asset	53.0				$ 32.6
Interest Expense	48.8	$ 55.3
Cash Received
Deferred taxes on unrealized gains (losses), arising during the period	(12.7)
Foreign Currency Translation [Member]
Derivative [Line Items]
Unrealized (losses) gains, arising during the period	(18.0)
Cash Received
Deferred taxes on unrealized gains (losses), arising during the period	1.3
Foreign Exchange Contract [Member]
Cash Received
Unrealized currency derivative contract gain (loss)	13.0	32.9
Foreign Exchange Contract [Member] | Currency Derivative Contracts [Member]
Derivative [Line Items]
Unrealized (losses) gains, arising during the period	28.8
Cash Received
Deferred taxes on unrealized gains (losses), arising during the period	(15.8)
Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	163.4
Cash Received
Unrealized currency derivative contract gain (loss)	(5.6)	$ 0.0
Interest Rate Swap [Member] | Currency Derivative Contracts [Member]
Derivative [Line Items]
Unrealized (losses) gains, arising during the period	(7.4)
Cash Received
Deferred taxes on unrealized gains (losses), arising during the period	1.8
Interest Rate Swap [Member] | AOCI Attributable to Parent [Member]
Cash Received
Unrealized currency derivative contract gain (loss)	7.4
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Level 2 [Member]
Derivative [Line Items]
Hedge Asset	53.0
Hedge Liability	(50.1)
Unrealized currency derivative contracts (loss) gain	28.7
Realized Gains	8.3
Cash Received
Total	32.5
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Level 2 [Member] | Interest Expense [Member]
Derivative [Line Items]
Interest Expense	3.0
Designated as Hedging Instrument [Member] | Derivatives Outstanding [Member] | Level 2 [Member]
Derivative [Line Items]
Hedge Asset	53.0
Hedge Liability	(50.1)
Unrealized currency derivative contracts (loss) gain	11.9
Realized Gains	3.6
Cash Received
Cash Paid	0.0
Designated as Hedging Instrument [Member] | Derivatives Outstanding [Member] | Level 2 [Member] | Interest Expense [Member]
Derivative [Line Items]
Interest Expense	1.9
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, One [Member]
Derivative [Line Items]
Notional Amount | €				€ 185.0
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, One [Member] | Level 2 [Member]
Derivative [Line Items]
Hedge Asset	10.3
Hedge Liability	(2.6)
Unrealized currency derivative contracts (loss) gain	(0.3)
Realized Gains	3.6
Cash Received
Cash Paid	0.0
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, One [Member] | Level 2 [Member] | Interest Expense [Member]
Derivative [Line Items]
Interest Expense	0.6
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, Two [Member] | KWE [Member]
Derivative [Line Items]
Notional Amount | €				€ 240.8
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, Two [Member] | Level 2 [Member] | KWE [Member]
Derivative [Line Items]
Hedge Asset	0.0
Hedge Liability	(46.4)
Unrealized currency derivative contracts (loss) gain	(9.9)
Realized Gains	0.0
Cash Received
Cash Paid	0.0
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, Two [Member] | Level 2 [Member] | KWE [Member] | Interest Expense [Member]
Derivative [Line Items]
Interest Expense	0.0
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, Three [Member] | Level 2 [Member] | KWE [Member]
Derivative [Line Items]
Hedge Asset	0.0
Hedge Liability	0.0
Unrealized currency derivative contracts (loss) gain	(25.4)
Realized Gains	0.0
Cash Received
Cash Paid	0.0
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, Three [Member] | Level 2 [Member] | KWE [Member] | Interest Expense [Member]
Derivative [Line Items]
Interest Expense	0.0
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, Four [Member]
Derivative [Line Items]
Notional Amount | £			£ 460.0
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, Four [Member] | Level 2 [Member]
Derivative [Line Items]
Hedge Asset	42.7
Hedge Liability	(1.1)
Unrealized currency derivative contracts (loss) gain	47.5
Realized Gains	0.0
Cash Received
Cash Paid	0.0
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, Four [Member] | Level 2 [Member] | Interest Expense [Member]
Derivative [Line Items]
Interest Expense	1.3
Designated as Hedging Instrument [Member] | Derivative Settled [Member] | Level 2 [Member]
Derivative [Line Items]
Hedge Asset	0.0
Hedge Liability	0.0
Unrealized currency derivative contracts (loss) gain	16.8
Realized Gains	4.7
Cash Received
Cash Received	32.5
Designated as Hedging Instrument [Member] | Derivative Settled [Member] | Level 2 [Member] | Interest Expense [Member]
Derivative [Line Items]
Interest Expense	1.1
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, Five [Member] | Level 2 [Member]
Derivative [Line Items]
Hedge Asset	0.0
Hedge Liability	0.0
Unrealized currency derivative contracts (loss) gain	0.4
Realized Gains	4.7
Cash Received
Cash Received	13.6
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, Five [Member] | Level 2 [Member] | Interest Expense [Member]
Derivative [Line Items]
Interest Expense	0.6
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, Six [Member] | Level 2 [Member]
Derivative [Line Items]
Hedge Asset	0.0
Hedge Liability	0.0
Unrealized currency derivative contracts (loss) gain	16.4
Realized Gains	0.0
Cash Received
Cash Received	18.9
Designated as Hedging Instrument [Member] | Foreign Exchange Contract, Six [Member] | Level 2 [Member] | Interest Expense [Member]
Derivative [Line Items]
Interest Expense	$ 0.5