Goodwill and Other Intangibles (Other Intangible Assets Subject to Amortization and Capitalized Software) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Other Intangible Assets
Intangible Asset, Acquired, Finite-Lived [Line Items]
Gross Carrying Amount	$ 136.8		$ 136.8		$ 127.0
Less: Accumulated Amortization	77.9		77.9		68.9
Net Book Value	58.9	$ 64.9	58.9	$ 64.9	58.1
Finite-Lived Intangible Assets [Roll Forward]
Balance	61.2	64.4	58.1	71.6
Amortization	(2.4)	(2.4)	(6.8)	(7.1)
Foreign Exchange Rates	0.1	2.9	7.6	0.4
Balance	58.9	64.9	58.9	64.9
Computer Software
Intangible Asset, Acquired, Finite-Lived [Line Items]
Gross Carrying Amount	4,934.0		4,934.0		4,259.6
Less: Accumulated Amortization	2,582.1		2,582.1		2,104.5
Net Book Value	2,351.9		2,351.9		$ 2,155.1
Finite-Lived Intangible Assets [Roll Forward]
Balance			2,155.1
Amortization	(168.8)	$ (153.1)	(499.7)	$ (444.1)
Balance	$ 2,351.9		$ 2,351.9