Other Comprehensive Income (Loss) (Schedule of Component of Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
AOCI Attributable to Parent [Abstract]
Beginning balance	$ 10,649.8
Other comprehensive income (loss) before reclassifications	(518.2)	$ 247.7	$ 1,795.4
Net amount reclassified from accumulated other comprehensive loss	(35.8)	(250.8)	(357.9)
Other comprehensive income (loss), net of tax (Note 17)	(482.4)	498.5	2,153.3
Ending balance	10,771.9	10,649.8
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent [Abstract]
Beginning balance	(3,844.6)	(4,343.1)	(6,496.4)
Other comprehensive income (loss), net of tax (Note 17)	(482.4)	498.5	2,153.3
Ending balance	(4,327.0)	(3,844.6)	(4,343.1)
Foreign currency translation gains/losses
AOCI Attributable to Parent [Abstract]
Beginning balance	(1,874.2)	(1,550.2)	(1,427.5)
Other comprehensive income (loss) before reclassifications	78.9	(324.4)	(122.7)
Net amount reclassified from accumulated other comprehensive loss	23.7	(0.4)	0.0
Other comprehensive income (loss), net of tax (Note 17)	55.2	(324.0)	(122.7)
Ending balance	(1,819.0)	(1,874.2)	(1,550.2)
Net unrealized gains/losses on available-for-sale securities
AOCI Attributable to Parent [Abstract]
Beginning balance	(37.1)	3.7	14.8
Other comprehensive income (loss) before reclassifications	10.1	(52.2)	(11.9)
Net amount reclassified from accumulated other comprehensive loss	(0.8)	(11.4)	(0.8)
Other comprehensive income (loss), net of tax (Note 17)	10.9	(40.8)	(11.1)
Ending balance	(26.2)	(37.1)	3.7
Retirement benefit plans
AOCI Attributable to Parent [Abstract]
Beginning balance	(2,062.3)	(2,583.6)	(4,751.0)
Other comprehensive income (loss) before reclassifications	(686.9)	291.5	1,823.4
Net amount reclassified from accumulated other comprehensive loss	(51.9)	(229.8)	(344.0)
Other comprehensive income (loss), net of tax (Note 17)	(635.0)	521.3	2,167.4
Ending balance	(2,697.3)	(2,062.3)	(2,583.6)
Net unrealized gains/losses on cash flow hedges
AOCI Attributable to Parent [Abstract]
Beginning balance	129.0	(213.0)	(332.7)
Other comprehensive income (loss) before reclassifications	79.7	332.8	106.6
Net amount reclassified from accumulated other comprehensive loss	(6.8)	(9.2)	(13.1)
Other comprehensive income (loss), net of tax (Note 17)	86.5	342.0	119.7
Ending balance	$ 215.5	$ 129.0	$ (213.0)