Quarterly Data (Unaudited) (Parenthetical) (Details) - USD ($) $ in Millions			1 Months Ended	9 Months Ended			12 Months Ended
	Sep. 29, 2023	Jan. 17, 2022	Nov. 30, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2023	[1],[2]	Dec. 31, 2022		Dec. 31, 2021
Quarterly Financial Information Disclosure [Line Items]
Impairment Charge				$ 0.0	$ 0.0	$ 0.0	$ 55.1		$ 50.0	[1],[2]	$ 0.0
One-time loss on disposition		$ (8.0)			$ (4.1)				(2.1)
Selling and Administrative Expenses
Quarterly Financial Information Disclosure [Line Items]
One-time loss on disposition	$ (1.3)	(9.7)	$ (1.2)						(0.9)
Interest and Other Expenses (Income), Net
Quarterly Financial Information Disclosure [Line Items]
One-time loss on disposition		$ (1.7)							$ (1.2)

[1] Balances were net of accumulated impairment loss of $694.2 ($177.0 related to Northern Europe, $3.8 related to APME, $235.2 related to Right Management and $278.2 related to Corporate) as of December 31, 2022; and $749.3 ($232.1 related to Northern Europe, $3.8 related to APME, $235.2 related to Right Management and $278.2 related to Corporate) as of December 31, 2023.

[2] The impairment charges relate to our Netherlands reporting unit, which was recorded during the fourth quarter of 2022 and 2023, respectively. See Note 1 to the Consolidated Financial Statements for further information.