Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Alternative minimum tax and other credit carryforwards	$ 1,074.0	$ 998.0
Accrued and unfunded compensation and employee benefits	265.6	239.9
Amortizable intangible assets	92.7	61.3
Compensation expense related to stock options	5.8	14.4
Accrued liabilities	112.1	65.7
Accrued pension liability	1.5	9.3
Investments	3.1	1.3
Net operating loss carryforwards	32.7	36.1
Capital loss carryforwards	8.9	9.0
Revenue recognition	3.7
Lease liabilities	106.4	96.3
Hedging instruments	27.3	34.6
Other	5.0	2.8
Total deferred tax assets	1,738.8	1,568.7
Valuation allowance for deferred tax assets	(154.9)	(94.9)
Deferred tax assets	1,583.9	1,473.8
Nondeductible amortizable intangible assets	394.7	316.9
Investment-related partnerships	4.6	8.5
Depreciable fixed assets	16.2	32.4
Right-of-use assets	96.9	92.2
Revenue recognition		33.1
Other prepaid items	8.8	12.0
Total deferred tax liabilities	521.2	495.1
Net deferred tax assets	$ 1,062.7	$ 978.7