Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

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,
(in millions)	2018		2017		2016
			(as adjusted)		(as adjusted)
Domestic	$	762.3	$	608.3	$	635.5
Foreign	78.2		52.4		37.7
Total	$	840.5	$	660.7	$	673.2

Schedule of Components of Income Tax Expense (Benefit)

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

	Year Ended December 31,
(in millions)	2018			2017			2016
				(as adjusted)			(as adjusted)
Current:
Federal	$	192.6		$	258.9		$	295.6
State	43.3			29.8			34.9
Foreign	17.7			21.3			16.8
Total current	253.6			310.0			347.3
Deferred:
Domestic	(52.7		)	(167.6		)	(90.5		)
Foreign	(3.4		)	(4.8		)	(8.7		)
Total deferred	(56.1		)	(172.4		)	(99.2		)
Income tax expense	$	197.5		$	137.6		$	248.1

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 is as follows:

	Year Ended December 31,
(dollars in millions)	2018					2017					2016
						(as adjusted)					(as adjusted)
Statutory federal income tax rate	$	176.5		21.0	%	$	231.1		35.0	%	$	235.5		35.0	%
State taxes, net of federal effect	31.1			3.7		18.3			2.8		17.7			2.6
Excess tax benefit of equity awards	(19.7		)	(2.3	)	(36.2		)	(5.5	)	(1.6		)	(0.2	)
Effect of rates different than statutory	0.6			0.1		(6.3		)	(1.0	)	(4.6		)	(0.7	)
Tax on foreign earnings	2.8			0.3		1.0			0.1		0.8			0.1
Effect of UK tax rate change on deferred taxes	—			—		—			—		(1.5		)	(0.2	)
Effect of US Tax Cuts and Jobs Act on deferred taxes and repatriation tax	(1.9		)	(0.2	)	(75.5		)	(11.4	)	—			—
Other	8.1			0.9		5.2			0.8		1.8			0.3
Effective tax rate	$	197.5		23.5	%	$	137.6		20.8	%	$	248.1		36.9	%

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,
(in millions)	2018		2017
Deferred tax assets:
Equity compensation plans	$	17.7	$	18.7
Payroll and benefits	9.3		8.0
Deferred interest	—		6.8
Net operating loss and credit carryforwards, net	23.8		28.1
Rent	7.5		7.4
Accounts receivable	6.5		5.4
Other	10.0		9.5
Total deferred tax assets	74.8		83.9
Deferred tax liabilities:
Software and intangibles	148.6		194.5
Deferred income	—		18.6
International investments	19.2		19.2
Property and equipment	20.0		20.4
Other	11.7		12.0
Total deferred tax liabilities	199.5		264.7
Deferred tax asset valuation allowance	17.2		15.5
Net deferred tax liabilities	$	141.9	$	196.3

Schedule of Unrecognized Tax Benefits Roll Forward

Changes in the Company's unrecognized tax benefits at December 31, 2018, 2017 and 2016 were as follows:

	Year Ended December 31,
(in millions)	2018		2017		2016
Balance as of January 1, 2018	$	—	$	—	$	—
Additions for tax positions related to current year	15.1		—		—
Balance as of December 31, 2018	$	15.1	$	—	$	—