Components of Comprehensive Income, Net of Related Tax (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 720.4	$ 495.5	$ 1,320.9	$ 966.3
Other comprehensive income (loss) (OCI):
Unrealized gains (losses) on derivative contracts	1.0	(1.1)	37.1	21.2
Tax effect	(1.2)	(1.9)	(10.9)	(6.0)
Net current period OCI, unrealized gains (losses) on derivative contracts	(0.2)	(3.0)	26.2	15.2
Unrealized losses on marketable debt securities	(10.4)	(2.2)	(44.5)	(8.8)
Tax effect	2.6	0.6	11.1	2.2
Net current period OCI, unrealized gains and (losses) on marketable debt securities	(7.8)	(1.6)	(33.4)	(6.6)
Pension plans	19.9	13.4	30.2	26.3
Tax effect	(5.1)	(3.1)	(7.5)	(6.2)
Net current period OCI, pension plans	14.8	10.3	22.7	20.1
Foreign currency translation (losses) gains	(240.8)	81.1	(206.1)	(8.0)
Net other comprehensive (loss) income	(234.0)	86.8	(190.6)	20.7
Comprehensive income	$ 486.4	$ 582.3	$ 1,130.3	$ 987.0