Business Combinations (Schedule of Purchase Price Allocation) (Details) - USD ($) $ in Millions	Mar. 20, 2023	Jan. 03, 2023	Mar. 31, 2024	Dec. 31, 2023
Liabilities assumed:
Goodwill acquired on acquisition			$ 4,528.8	$ 4,537.0
IAA
Business Acquisition [Line Items]
Purchase price	$ 6,646.1
Assets acquired:
Cash and cash equivalents	166.6
Trade and other receivables	497.3
Inventory	57.1
Other current assets	28.0
Income taxes receivable	0.6
Property, plant and equipment	618.5
Operating lease right-of-use assets	1,289.7
Other non-current assets	34.8
Intangible assets	2,712.1
Liabilities assumed:
Auction proceeds payable	60.7
Trade and other liabilities	257.0
Current operating lease liability	77.5
Income taxes payable	3.5
Long-term operating lease liability	1,192.7
Other non-current liabilities	24.3
Deferred tax liabilities	689.5
Fair value of identifiable net assets acquired	3,099.5
Goodwill acquired on acquisition	$ 3,546.6
VeriTread
Business Acquisition [Line Items]
Purchase price		$ 32.4
Assets acquired:
Cash and cash equivalents		3.4
Trade and other receivables		0.9
Intangible assets		14.7
Liabilities assumed:
Trade and other liabilities		1.1
Fair value of identifiable net assets acquired		17.9
Redeemable non-controlling interest		(8.9)
Non-controlling interest		(1.8)
Goodwill acquired on acquisition		$ 25.2