Changes in Accumulated Other Comprehensive Income (Loss) by Component (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			$ 17,506.9
Reclassified out of AOCI	$ 3.7	$ 38.3	169.6	$ (28.7)
Net other comprehensive income (loss)	0.4	139.8	544.0	(111.5)
Ending balance	19,368.6	18,663.6	19,368.6	18,663.6
Derivative Contracts
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	4.9	16.8	32.5	(11.0)
Recorded into AOCI	(2.5)	(43.1)	(194.9)	53.2
Reclassified out of AOCI	2.6	36.8	167.4	(31.7)
Net other comprehensive income (loss)	0.1	(6.3)	(27.5)	21.5
Ending balance	5.0	10.5	5.0	10.5
Marketable Debt Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	16.7	(13.8)	(0.7)	(13.9)
Recorded into AOCI	2.9	27.5	20.3	28.9
Reclassified out of AOCI	0.4	(0.7)	0.4	(2.0)
Net other comprehensive income (loss)	3.3	26.8	20.7	26.9
Ending balance	20.0	13.0	20.0	13.0
Pension Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	69.9	(102.6)	69.7	(110.3)
Recorded into AOCI	(1.2)		(2.1)	4.9
Reclassified out of AOCI	0.7	2.2	1.8	5.0
Net other comprehensive income (loss)	(0.5)	2.2	(0.3)	9.9
Ending balance	69.4	(100.4)	69.4	(100.4)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(661.2)	(845.6)	(1,214.8)	(558.7)
Recorded into AOCI	(2.5)	117.1	551.1	(169.8)
Net other comprehensive income (loss)	(2.5)	117.1	551.1	(169.8)
Ending balance	(663.7)	(728.5)	(663.7)	(728.5)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(569.7)	(945.2)	(1,113.3)	(693.9)
Recorded into AOCI	(3.3)	101.5	374.4	(82.8)
Reclassified out of AOCI	3.7	38.3	169.6	(28.7)
Net other comprehensive income (loss)	0.4	139.8	544.0	(111.5)
Ending balance	$ (569.3)	$ (805.4)	$ (569.3)	$ (805.4)