Discontinued Operations and Disposal Groups (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Fortrea Senior Notes	$ 570.0
Disposal Group, Including Discontinued Operation, Fortrea Senior Notes Interest Rate	7.50%
Disposal Group, Including Discontinued Operation, Fortrea Distribution	$ 1,600.0
Disposal Group, Including Discontinued Operation, Fortrea Credit Facilities	1,520.0
Disposal Group, Including Discontinued Operation, Revenue	1,506.6	$ 3,012.9	$ 2,984.8
Disposal Group, Including Discontinued Operation, Costs of Goods Sold	1,244.5	2,336.7	2,352.9
Disposal Group, Including Discontinued Operation, Gross Profit (Loss)	262.1	676.2	631.9
Disposal Group, Including Discontinued Operation, General and Administrative Expense	184.1	233.5	261.8
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	31.9	65.7	140.1
Disposal group, including discontinued operations, goodwill and other asset impairment	0.0	9.8	0.0
Disposal Group, Including Discontinued Operation, Restructuring and other charges	3.0	29.8	19.1
Disposal Group, Including Discontinued Operation, Operating Income (Loss)	43.1	337.4	210.9
Disposal Group, Including Discontinued Operation, Interest Expense	(0.5)	(0.5)	(0.3)
Disposal Group, Including Discontinued Operation, Investment income (expense)	(1.2)
Disposal Group, Including Discontinued Operation, Interest Income		1.4	1.4
Disposal Group, Including Discontinued Operations, Other Nonoperating income (expense)	4.2	6.9	27.0
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax	45.6	345.2	239.0
Discontinued Operation, Tax Effect of Discontinued Operation	6.8	68.1	57.1
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	38.8	$ 277.1	$ 181.9
Fortrea Revolver due 2028
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Fortrea Credit Facilities	450.0
Fortrea Term Loan A maturing 2028
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Fortrea Credit Facilities	500.0
Fortrea Term Loan B maturing 2028
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Fortrea Credit Facilities	$ 570.0