Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Earnings Before Income Taxes

Earnings before income taxes were derived from the following sources:

	2017		2016	2015
Domestic	$	809.4	739.4	786.0
Foreign	63.7		50.3	40.1
Earnings before income taxes	$	873.1	789.7	826.1

Components of Income Tax Expense (Benefit)

Components of income tax expense (benefit) were as follows:

2017:	Current		Deferred		Total
Federal	$	270.6	(33.1	)	237.5
State	33.2		3.3		36.5
Foreign	20.5		—		20.5
Income tax expense	$	324.3	(29.8	)	294.5

2016:	Current		Deferred	Total
Federal	$	223.9	23.2	247.1
State	28.2		1.2	29.4
Foreign	12.6		1.2	13.8
Income tax expense	$	264.7	25.6	290.3

2015:	Current		Deferred	Total
Federal	$	256.7	7.4	264.1
State	31.3		0.2	31.5
Foreign	13.7		0.4	14.1
Income tax expense	$	301.7	8.0	309.7

Difference In Income Tax Expense And Expected Expense

Income tax expense in the accompanying consolidated financial statements differed from the expected expense as follows:

	2017			2016		2015
Federal income tax expense at the 'expected' rate of 35%	$	305.6		276.4		289.1
Increase (decrease) attributed to:
State income taxes, net of federal benefit	21.5			20.0		21.6
Transition tax	6.5			—		—
Effect of 2018 deferred rate change	(30.8		)	—		—
Other, net	(8.3		)	(6.1	)	(1.0	)
Total income tax expense	$	294.5		290.3		309.7
Effective income tax rate	33.7		%	36.8	%	37.5	%

Summary of Temporary Differences That Give Rise to Deferred Income Tax Assets And Liabilities

The tax effects of temporary differences that give rise to deferred income tax assets and liabilities at year end consisted of the following:

	2017			2016
Deferred income tax assets (liabilities):
Inventory costing and valuation methods	$	3.6		4.8
Allowance for doubtful accounts	3.0			4.3
Insurance reserves	8.4			11.5
Promotions payable	1.3			1.7
Stock-based compensation	5.2			6.8
Federal and state benefit of uncertain tax positions	0.9			1.9
Foreign net operating loss and credit carryforwards	4.2			5.1
Foreign valuation allowances	(2.8		)	(4.0	)
Other, net	0.8			2.1
Total deferred income tax assets	24.6			34.2
Property and equipment	(75.2		)	(114.8	)
Total deferred income tax liabilities	(75.2		)	(114.8	)
Deferred income tax liabilities	$	(50.6	)	(80.6	)

Reconciliation of The Beginning and Ending Amount of Total Gross Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of total gross unrecognized tax benefits was as follows:

	2017			2016
Balance at beginning of year:	$	5.4		5.4
Increase related to prior year tax positions	0.4			0.2
Decrease related to prior year tax positions	(0.5		)	—
Increase related to current year tax positions	0.7			0.8
Decrease related to statute of limitation lapses	(1.1		)	(1.0	)
Settlements	(0.5		)	—
Balance at end of year:	$	4.4		5.4