Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Income before Income Tax, Domestic and Foreign

Income before income taxes was taxed under the following jurisdictions:

	Year Ended December 31,
	2023		2022		2021
Domestic	$	1,298.1	$	1,355.6	$	1,186.7
Foreign	152.1		132.2		111.1
Total	$	1,450.2	$	1,487.8	$	1,297.8

Schedule of Components of Income Tax Expense (Benefit)

Components of Income tax expense (benefit) consist of the following:

	Year Ended December 31,
	2023		2022		2021
Current:
Federal	$	267.3	$	281.8	$	235.6
State	69.7		75.8		52.9
Foreign	41.6		33.9		27.4
Total current	378.6		391.5		315.9
Deferred:
Domestic	(29.3)		(15.0)		(8.7)
Foreign	(3.4)		(3.2)		2.0
Total deferred	(32.7)		(18.2)		(6.7)
Income tax expense	$	345.9	$	373.3	$	309.2

Schedule of Effective Income Tax Rate Reconciliation

The reconciliation between the statutory tax rate expressed as a percentage of income before income taxes and the effective tax rate was as follows:

	Year Ended December 31,
	2023				2022				2021
Statutory federal income tax rate	$	304.5	21.0	%	$	312.4	21.0	%	$	272.5	21.0	%
State taxes, net of federal effect	55.8		3.8		61.1		4.1		50.3		3.9
Excess tax benefit of equity awards	(29.6)		(2.0)		(12.0)		(0.8)		(30.1)		(2.3)
Tax on foreign earnings	8.5		0.6		3.0		0.2		1.7		0.1
Effect of tax law changes	—		—		—		—		4.8		0.4
Other	6.7		0.5		8.8		0.6		10.0		0.7
Effective tax rate	$	345.9	23.9	%	$	373.3	25.1	%	$	309.2	23.8	%

Schedule of Deferred Tax Assets and Liabilities

The tax effect of temporary differences that give rise to net deferred income tax liabilities is presented below.

	December 31,
	2023		2022
Deferred tax assets:
Contract liabilities	$	38.4	$	46.3
Equity compensation plans	34.5		31.3
Net operating loss and credit carryforwards, net	17.0		17.0
Payroll and benefits	17.2		24.3
Operating lease liabilities	45.6		48.5
Accounts receivable	20.1		18.1
Other	19.9		19.5
Total deferred tax assets	192.7		205.0
Deferred tax liabilities:
Acquisition-related intangibles	269.8		293.3
Property and equipment	22.4		38.1
Operating lease right-of-use assets	27.6		32.9
Other	26.7		27.1
Total deferred tax liabilities	346.5		391.4
Deferred tax asset valuation allowance	17.0		17.0
Net deferred tax liabilities	$	170.8	$	203.4

Schedule of Unrecognized Tax Benefits Roll Forward

Changes in the Company’s unrecognized tax benefits as of December 31, 2023, 2022 and 2021 were as follows:

	Year Ended December 31,
	2023		2022		2021
Balance as of January 1	$	18.7	$	18.4	$	18.3
Additions for current year and prior year	0.6		0.3		0.1
Balance as of December 31	$	19.3	$	18.7	$	18.4