Reclassification out of Accumulated Other Comprehensive Income ("AOCI") (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other comprehensive income (loss), net	$ 924.9	$ 497.5	$ (312.1)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	4,547.6
Other comprehensive (loss)/income before reclassification adjustments	1,170.3	652.8	(426.6)
Tax effect	(249.0)	(163.3)	100.0
Reclassification adjustments to net earnings	4.7	10.4	18.7
Tax effect	(1.1)	(2.4)	(4.2)
Ending balance	6,188.0	4,547.6
Accumulated Other Comprehensive Income/(Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other comprehensive income (loss), net	924.9	497.5	(312.1)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(1,808.3)	(2,305.8)	(1,993.7)
Ending balance	(883.4)	(1,808.3)	(2,305.8)
Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(378.8)	(340.8)	(354.2)
Other comprehensive (loss)/income before reclassification adjustments	89.0	(38.0)	13.4
Tax effect	0.0	0.0	0.0
Reclassification adjustments to net earnings	0.0	0.0	0.0
Tax effect	0.0	0.0	0.0
Ending balance	(289.8)	(378.8)	(340.8)
Net Gains/(Losses) on Available-for-sale Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(1,178.0)	(1,705.6)	(1,330.0)
Other comprehensive (loss)/income before reclassification adjustments	1,088.4	685.2	(500.3)
Tax effect	(250.7)	(162.2)	113.3
Reclassification adjustments to net earnings	1.7	5.9	14.7
Tax effect	(0.3)	(1.3)	(3.3)
Ending balance	(338.9)	(1,178.0)	(1,705.6)
Cash Flow Hedging Activities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(20.0)	(23.3)	(26.6)
Other comprehensive (loss)/income before reclassification adjustments	(15.6)	0.0	0.0
Tax effect	3.8	0.0	0.0
Reclassification adjustments to net earnings	5.4	4.4	4.4
Tax effect	(1.3)	(1.1)	(1.1)
Ending balance	(27.7)	(20.0)	(23.3)
Pension Liability
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(231.5)	(236.1)	(282.9)
Other comprehensive (loss)/income before reclassification adjustments	8.5	5.6	60.3
Tax effect	(2.1)	(1.1)	(13.3)
Reclassification adjustments to net earnings	(2.4)	0.1	(0.4)
Tax effect	0.5	0.0	0.2
Ending balance	$ (227.0)	$ (231.5)	$ (236.1)