Stockholders' Equity - Schedule of Components of Accumulated Other Comprehensive Income/(Loss) (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Beginning balance	$ 626.5	$ 552.8	$ 477.8	$ 448.3	$ 352.8	$ 355.6	$ 477.8	$ 355.6
Amounts reclassified from AOCL into earnings, net of tax	(1.7)			(10.5)			(17.4)	(43.0)
Ending balance	613.6	626.5	552.8	528.3	448.3	352.8	613.6	528.3
Investment Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Beginning balance	(60.8)	(49.4)	(69.4)	(44.9)	(21.2)	30.4	(69.4)	30.4
Unrealized gains/(losses)	(20.2)	(13.8)	24.1	(44.7)	(28.7)	(63.6)
Tax benefit/(expense)	3.5	2.4	(4.2)	7.9	5.0	11.9
Amounts reclassified from AOCL into earnings, net of tax	3.0		0.1	6.8		0.1	3.1	6.9
Ending balance	(74.5)	(60.8)	(49.4)	(74.9)	(44.9)	(21.2)	(74.5)	(74.9)
Hedging Activities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Beginning balance	(0.6)	10.2	20.5	47.1	24.0	18.7	20.5	18.7
Unrealized gains/(losses)	14.8	(3.1)	(2.2)	43.4	37.3	6.2
Tax benefit/(expense)	(0.1)	(0.1)	0.1	(0.5)	(0.3)
Amounts reclassified from AOCL into earnings, net of tax	(4.7)	(7.6)	(8.2)	(17.3)	(13.9)	(0.9)	(20.5)	(32.1)
Ending balance	9.4	(0.6)	10.2	72.7	47.1	24.0	9.4	72.7
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Beginning balance	(119.0)	(119.0)	(119.0)	(119.0)	(119.0)	(101.2)	(119.0)	(101.2)
Amounts reclassified from AOCL into earnings, net of tax						(17.8)		(17.8)
Ending balance	(119.0)	(119.0)	(119.0)	(119.0)	(119.0)	(119.0)	(119.0)	(119.0)
Total AOCL
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Beginning balance	(180.4)	(158.2)	(167.9)	(116.8)	(116.2)	(52.1)	(167.9)	(52.1)
Unrealized gains/(losses)	(5.4)	(16.9)	21.9	(1.3)	8.6	(57.4)
Tax benefit/(expense)	3.4	2.3	(4.1)	7.4	4.7	11.9
Amounts reclassified from AOCL into earnings, net of tax	(1.7)	(7.6)	(8.1)	(10.5)	(13.9)	(18.6)
Ending balance	$ (184.1)	$ (180.4)	$ (158.2)	$ (121.2)	$ (116.8)	$ (116.2)	$ (184.1)	$ (121.2)