Summary of Significant Accounting Policies (Details) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($) shares	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($) shares
Operating Lease, Right-of-Use Asset	$ 1,037.8	$ 1,162.6
Operating Lease, Liability	1,293.5
Revenue, remaining performance obligation, amount	598.5
Retirement of treasury stock, amount	$ 0.1	(0.0)	$ (0.0)
ERP Systems, Useful Life	10
Minimum Remaining Lease Term	1 year
Maximum Remaining Lease Term	12 years
Leasehold Improvements, Useful Life	the shorter of the useful life or the remaining lease term
Number of Reporting Units for Purposes of Annual Goodwill Impairment Test	10
Foreign Currency Transaction pre-tax Gain (Loss)	$ 2.2	5.7	(2.5)
Minimum
Furniture and Equipment, Useful Life	3 years
Buildings, Useful Life	10 years
Identifiable Intangible Assets, Useful Life	10 years
Other Internal Use Software, Useful Life	3
Maximum
Furniture and Equipment, Useful Life	7 years
Buildings, Useful Life	35 years
Identifiable Intangible Assets, Useful Life	15 years
Other Internal Use Software, Useful Life	7
Common Stock [Member]
Retirement of treasury stock, amount	$ 1.2	0.9	0.7
Additional Paid-in Capital [Member]
Retirement of treasury stock, amount	$ 363.4	$ 339.5	$ 199.2
Common Stock, Shares Issued [Member]
Retirement of treasury stock, shares | shares	(11.6)	(9.3)	(7.2)
Treasury Stock, Common
Retirement of treasury stock, amount	$ (364.5)	$ (340.4)	$ (199.9)