Segment Information - Schedule of Segment Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Net sales	$ 5,199.1	$ 4,872.7
Cost of sales	4,076.8	3,809.4
Gross profit	1,122.3	1,063.3
Other segment items	760.9	735.3
Operating income	361.4	328.0
Depreciation and amortization expense	74.9	67.3
Operating Segments | Corporate
Segment Reporting Information [Line Items]
Net sales	2,236.0	2,135.9
Cost of sales	1,701.1	1,628.4
Gross profit	534.9	507.5
Other segment items	314.2	329.5
Operating income	220.7	178.0
Depreciation and amortization expense	27.4	19.8
Operating Segments | Small Business
Segment Reporting Information [Line Items]
Net sales	404.6	380.9
Cost of sales	316.0	291.1
Gross profit	88.6	89.8
Other segment items	45.2	43.3
Operating income	43.4	46.5
Depreciation and amortization expense	1.4	1.0
Operating Segments | Public
Segment Reporting Information [Line Items]
Net sales	1,878.1	1,724.7
Cost of sales	1,511.5	1,379.4
Gross profit	366.6	345.3
Other segment items	225.4	219.3
Operating income	141.2	126.0
Depreciation and amortization expense	15.7	13.4
Operating Segments | Other
Segment Reporting Information [Line Items]
Net sales	680.4	631.2
Cost of sales	548.2	510.5
Gross profit	132.2	120.7
Other segment items	93.1	95.4
Operating income	39.1	25.3
Depreciation and amortization expense	6.8	7.1
Headquarters
Segment Reporting Information [Line Items]
Net sales	0.0	0.0
Cost of sales	0.0	0.0
Gross profit	0.0	0.0
Other segment items	83.0	47.8
Operating income	(83.0)	(47.8)
Depreciation and amortization expense	$ 23.6	$ 26.0