Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

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,
	2020		2019		2018
Domestic	$	934.3	$	854.1	$	762.3
Foreign	68.0		95.6		78.2
Total	$	1,002.3	$	949.7	$	840.5

Schedule of Components of Income Tax Expense (Benefit)

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

	Year Ended December 31,
	2020		2019		2018
Current:
Federal	$	166.5	$	224.7	$	192.6
State	49.2		56.1		43.3
Foreign	18.3		20.0		17.7
Total current	234.0		300.8		253.6
Deferred:
Domestic	(18.8)		(83.0)		(52.7)
Foreign	(1.4)		(4.9)		(3.4)
Total deferred	(20.2)		(87.9)		(56.1)
Income tax expense	$	213.8	$	212.9	$	197.5

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,
	2020				2019				2018
Statutory federal income tax rate	$	210.5	21.0	%	$	199.4	21.0	%	$	176.5	21.0	%
State taxes, net of federal effect	36.0		3.6		35.4		3.7		31.1		3.7
Excess tax benefit of equity awards	(28.8)		(2.9)		(26.8)		(2.8)		(19.7)		(2.3)
Effect of rates different than statutory	(0.8)		(0.1)		0.8		0.1		0.6		0.1
Tax on foreign earnings	1.0		0.1		2.1		0.2		2.8		0.3
Effect of tax law changes	(6.8)		(0.7)		—		—		(1.9)		(0.2)
Other	2.7		0.3		2.0		0.2		8.1		0.9
Effective tax rate	$	213.8	21.3	%	$	212.9	22.4	%	$	197.5	23.5	%

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. Reclassifications have been made to conform to current year presentation.

	December 31,
	2020		2019
Deferred tax assets:
Contract liabilities	$	13.2	$	46.3
Equity compensation plans	20.1		21.1
Net operating loss and credit carryforwards, net	22.9		20.1
Payroll and benefits	21.8		9.6
Operating lease liabilities	47.5		41.0
Accounts receivable	26.0		15.6
Other	15.9		14.1
Total deferred tax assets	167.4		167.8
Deferred tax liabilities:
Acquisition-related intangibles	76.5		112.2
Property and equipment	39.9		27.0
International investments	19.2		19.2
Operating lease right-of-use assets	32.5		33.7
Other	23.3		17.5
Total deferred tax liabilities	191.4		209.6
Deferred tax asset valuation allowance	16.9		16.8
Net deferred tax liabilities	$	40.9	$	58.6

Schedule of Unrecognized Tax Benefits Roll Forward

Changes in the Company's unrecognized tax benefits as of December 31, 2020, 2019 and 2018 were as follows:

	Year Ended December 31,
	2020		2019		2018
Balance as of January 1	$	17.7	$	15.1	$	—
Additions for tax positions related to current year	0.1		2.6		15.1
Additions for tax positions related to prior year	0.5		—		—
Balance as of December 31	$	18.3	$	17.7	$	15.1