Discontinued Operations - Disposal Group's Assets and Liabilities Presented as Discontinued Operations (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Current assets
Cash and cash equivalents	$ 5.4	$ 1.3
Total current assets from discontinued operations	333.3	460.0
Total noncurrent assets from discontinued operations	581.7	570.2
Current liabilities
Total current liabilities from discontinued operations	268.8	338.5
Total noncurrent liabilities from discontinued operations	83.0	85.7
Disposal Group [Member]
Current assets
Cash and cash equivalents	5.4	1.3
Receivables, less allowances of $3.0 and $2.9	278.3	400.9
Inventory, materials and supplies	9.4	18.8
Prepaid expenses	28.3	27.6
Other current assets	11.9	11.4
Total current assets from discontinued operations	333.3	460.0
Property, plant and equipment, net	81.9	73.4
Goodwill	153.2	154.3
Intangible assets, net	294.9	300.2
Deferred income tax assets	2.5	2.8
Other noncurrent assets	49.2	39.5
Total noncurrent assets from discontinued operations	581.7	570.2
Total assets from discontinued operations	915.0	1,030.2
Current liabilities
Current portion of long-term debt	6.3	6.7
Accounts payable	185.1	264.9
Unearned revenue and customer deposits	26.8	25.3
Accrued taxes	2.0	4.3
Accrued payroll and benefits	30.3	16.5
Other current liabilities	18.3	20.8
Total current liabilities from discontinued operations	268.8	338.5
Long-term debt, less current portion	5.4	6.3
Deferred income tax liability	46.0	52.3
Other noncurrent liabilities	31.6	27.1
Total noncurrent liabilities from discontinued operations	83.0	85.7
Total liabilities from discontinued operations	$ 351.8	$ 424.2