Lease Accounting - Schedule of Aggregate Lease Costs by Lease Classification (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Lease Cost [Line Items]
Total operating lease costs		$ 89.1	$ 89.2	$ 255.3	$ 264.8
Total finance lease costs		4.8	4.2	14.2	12.7
Depreciation and Amortization
Lease Cost [Line Items]
Amortization of leased assets		3.5	3.0	10.0	9.0
Interest Expense
Lease Cost [Line Items]
Interest on lease liabilities		1.3	1.2	4.2	3.7
Equipment | Utilities and Other
Lease Cost [Line Items]
Total operating lease costs	[1]	1.2	0.7	2.8	3.4
Real Estate | Facility Lease Expense
Lease Cost [Line Items]
Total operating lease costs	[1]	$ 87.9	$ 88.5	$ 252.5	$ 261.4

[1] Includes short-term lease payments, variable lease payments and office and equipment lease payments reflected in general and administrative expense as set forth in the following table for the periods presented: