Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), net of tax beginning balance			$ (106.7)	$ (299.0)
Balance, January 1, 2018	$ (110.4)	$ (171.8)	(110.4)	(171.8)
Other comprehensive income (loss), before reclassifications, net of tax			30.8	78.2
Amounts reclassified from accumulated other comprehensive income, net of tax			(34.5)	49.0
Other comprehensive income (loss), net of tax	4.8	2.4	(3.7)	127.8
Accumulated other comprehensive income (loss), net of tax ending balance	(110.4)	(171.8)	(110.4)	(171.8)
Other comprehensive income (loss), net of tax	4.8	2.5	(3.7)	127.2
Unrealized gains (losses) on securities available for sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), net of tax beginning balance			(2.2)	1.4
Balance, January 1, 2018	(20.2)	0.1	(20.2)	0.1
Other comprehensive income (loss), before reclassifications, net of tax			(19.1)	(2.0)
Amounts reclassified from accumulated other comprehensive income, net of tax			1.1	0.7
Other comprehensive income (loss), net of tax			(18.0)	(1.3)
Accumulated other comprehensive income (loss), net of tax ending balance	(20.2)	0.1	(20.2)	0.1
Unrealized gains (losses) on cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), net of tax beginning balance			53.8	(179.0)
Balance, January 1, 2018	126.9	(40.4)	126.9	(40.4)
Other comprehensive income (loss), before reclassifications, net of tax			129.5	90.2
Amounts reclassified from accumulated other comprehensive income, net of tax			(56.4)	48.4
Other comprehensive income (loss), net of tax			73.1	138.6
Accumulated other comprehensive income (loss), net of tax ending balance	126.9	(40.4)	126.9	(40.4)
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	(8.5)
Balance, January 1, 2018	0.0	11.6	0.0	11.6
Other comprehensive income (loss), before reclassifications, net of tax			12.6	20.2
Amounts reclassified from accumulated other comprehensive income, net of tax			(38.1)	(0.1)
Other comprehensive income (loss), net of tax			(25.5)	20.1
Accumulated other comprehensive income (loss), net of tax ending balance	0.0	11.6	0.0	11.6
Unfunded status of postretirement benefit plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), net of tax beginning balance			(44.8)	(66.3)
Balance, January 1, 2018	(42.1)	(63.9)	(42.1)	(63.9)
Other comprehensive income (loss), before reclassifications, net of tax			2.7	2.4
Amounts reclassified from accumulated other comprehensive income, net of tax			0.0	0.0
Other comprehensive income (loss), net of tax			2.7	2.4
Accumulated other comprehensive income (loss), net of tax ending balance	(42.1)	(63.9)	(42.1)	(63.9)
Currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), net of tax beginning balance			(139.0)	(46.6)
Balance, January 1, 2018	(175.0)	(79.2)	(175.0)	(79.2)
Other comprehensive income (loss), before reclassifications, net of tax			(94.9)	(32.6)
Amounts reclassified from accumulated other comprehensive income, net of tax			58.9	0.0
Other comprehensive income (loss), net of tax			(36.0)	(32.6)
Accumulated other comprehensive income (loss), net of tax ending balance	$ (175.0)	$ (79.2)	$ (175.0)	$ (79.2)