Acquisitions and Dispositions - Historical revenues from services (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Revenues from services		$ 20,724.4	$ 18,001.0	$ 20,863.5
Net earnings		382.4	23.8	$ 465.7
Ettain Group Member
Business Acquisition [Line Items]
Revenues from services	$ 182.7	21,269.1	18,731.0
Net earnings		$ 425.4	$ 40.1