Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net income	$ 300.0	$ 199.0
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	132.9	129.5
Equity-based compensation expense	19.1	23.6
Deferred income taxes	(28.1)	(40.3)
Net loss on extinguishments of long-term debt	0.0	57.4
Other	5.1	3.2
Changes in assets and liabilities:
Accounts receivable	(295.2)	(156.0)
Merchandise inventory	(167.7)	(52.5)
Other assets	(62.2)	(125.6)
Accounts payable-trade	386.8	311.8
Other liabilities	41.6	26.1
Net cash provided by operating activities	332.3	376.2
Cash flows used in investing activities:
Capital expenditures	(33.6)	(36.8)
Net cash used in investing activities	(33.6)	(36.8)
Cash flows used in financing activities:
Proceeds from borrowings under revolving credit facilities	488.1	67.7
Repayments of borrowings under revolving credit facilities	(474.4)	(13.7)
Repayments of long-term debt	(7.5)	(7.5)
Proceeds from issuance of long-term debt	0.0	2,083.0
Payments to extinguish long-term debt	0.0	(2,121.3)
Payments of debt financing fees	(1.0)	(9.6)
Net change in accounts payable-inventory financing	(110.4)	(85.1)
Premium payments on interest rate cap agreements	(12.6)	0.0
Proceeds from stock option exercises	19.9	7.4
Proceeds from Coworker Stock Purchase Plan	5.4	4.7
Repurchases of common stock	(176.4)	(359.4)
Payment of incentive compensation plan withholding taxes	(8.7)	(42.0)
Dividends	(63.8)	(50.3)
Other	3.2	(0.6)
Net cash used in financing activities	(338.2)	(526.7)
Effect of exchange rate changes on cash and cash equivalents	(4.0)	2.6
Net decrease in cash and cash equivalents	(43.5)	(184.7)
Cash and cash equivalents—beginning of period	144.2	263.7
Cash and cash equivalents—end of period	100.7	79.0
Supplementary disclosure of cash flow information:
Interest paid	(74.5)	(76.8)
Taxes paid, net	$ (118.4)	$ (96.5)