Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Alternative minimum tax and other credit carryforwards	$ 867.3	$ 772.7
Accrued and unfunded compensation and employee benefits	364.4	321.8
Amortizable intangible assets	122.9	69.3
Compensation expense related to stock options	18.3	11.1
Accrued liabilities	129.9	126.6
Accrued pension liability	0.0	3.1
Investments	1.2	2.6
Net operating loss carryforwards	172.7	129.4
Capital loss carryforwards	8.5	8.1
Other tax attributes	34.7
Depreciable fixed assets	13.2
Lease liabilities	103.4	96.5
Capitalized indirect property costs	0.2	394.1
Revenue recognition	42.1	0.0
Other	10.1	4.3
Total deferred tax assets	1,888.9	1,939.6
Valuation allowance for deferred tax assets	(195.8)	(135.2)
Deferred tax assets	1,693.1	1,804.4
Nondeductible amortizable intangible assets	531.7	433.9
Accrued pension liability	1.7	0.0
Investment-related partnerships	6.5	6.6
Depreciable fixed assets	0.0	46.5
Right-of-use assets	95.0	88.6
Hedging instruments	38.2	10.7
Other prepaid items	17.4	11.8
Total deferred tax liabilities	690.5	598.1
Net deferred tax assets	$ 1,002.6	$ 1,206.3