Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), net of tax beginning balance			$ (164.9)	$ (106.7)
Balance, January 1, 2018	$ (159.3)	$ (163.6)	(159.3)	(163.6)
Other comprehensive income (loss), before reclassifications, net of tax			10.0	40.4
Amounts reclassified from accumulated other comprehensive income, net of tax			(4.4)	(97.3)
Other comprehensive income (loss), net of tax	13.5	(53.2)	5.6	(56.9)
Accumulated other comprehensive income (loss), net of tax ending balance	(159.3)	(163.6)	(159.3)	(163.6)
Other comprehensive income (loss), net of tax	13.5	(53.2)	5.6	(56.9)
Gains (losses) on securities available for sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), net of tax beginning balance			(15.7)	(2.2)
Balance, January 1, 2018	0.0	(21.2)	0.0	(21.2)
Other comprehensive income (loss), before reclassifications, net of tax			2.3	(26.4)
Amounts reclassified from accumulated other comprehensive income, net of tax			13.4	7.4
Other comprehensive income (loss), net of tax			15.7	(19.0)
Accumulated other comprehensive income (loss), net of tax ending balance	0.0	(21.2)	0.0	(21.2)
Gains (losses) on cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), net of tax beginning balance			15.1	53.8
Balance, January 1, 2018	16.2	132.8	16.2	132.8
Other comprehensive income (loss), before reclassifications, net of tax			18.9	204.5
Amounts reclassified from accumulated other comprehensive income, net of tax			(17.8)	(125.5)
Other comprehensive income (loss), net of tax			1.1	79.0
Accumulated other comprehensive income (loss), net of tax ending balance	16.2	132.8	16.2	132.8
Gains (losses) on net investment hedge
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), net of tax beginning balance				25.5
Balance, January 1, 2018		0.0		0.0
Other comprehensive income (loss), before reclassifications, net of tax				12.6
Amounts reclassified from accumulated other comprehensive income, net of tax				(38.1)
Other comprehensive income (loss), net of tax				(25.5)
Accumulated other comprehensive income (loss), net of tax ending balance		0.0		0.0
Unfunded status of postretirement benefit plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), net of tax beginning balance			(1.1)	(44.8)
Balance, January 1, 2018	(0.5)	(40.6)	(0.5)	(40.6)
Other comprehensive income (loss), before reclassifications, net of tax			0.6	4.2
Amounts reclassified from accumulated other comprehensive income, net of tax			0.0	0.0
Other comprehensive income (loss), net of tax			0.6	4.2
Accumulated other comprehensive income (loss), net of tax ending balance	(0.5)	(40.6)	(0.5)	(40.6)
Currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), net of tax beginning balance			(163.2)	(139.0)
Balance, January 1, 2018	(175.0)	(234.6)	(175.0)	(234.6)
Other comprehensive income (loss), before reclassifications, net of tax			(11.8)	(154.5)
Amounts reclassified from accumulated other comprehensive income, net of tax			0.0	58.9
Other comprehensive income (loss), net of tax			(11.8)	(95.6)
Accumulated other comprehensive income (loss), net of tax ending balance	$ (175.0)	$ (234.6)	$ (175.0)	$ (234.6)