Business Combinations (Schedule of Purchase Price Allocation) (Details) - USD ($) $ in Millions	Mar. 20, 2023	Jan. 22, 2023	Jan. 03, 2023	Sep. 30, 2023	Dec. 31, 2022
Liabilities assumed:
Goodwill acquired on acquisition				$ 4,508.2	$ 948.8
IAA
Business Acquisition [Line Items]
Total cash consideration paid	$ 1,714.2	$ 1,700.0
Total fair value of consideration transferred	6,646.2
Assets acquired:
Cash and cash equivalents	164.9
Trade and other receivables	499.2
Prepaid consigned vehicle charges	8.7
Inventory	57.1
Other current assets	29.2
Income taxes receivable	2.6
Property, plant and equipment	627.5
Operating lease right-of-use assets	1,272.2
Other non-current assets	34.8
Intangible assets	2,712.1
Liabilities assumed:
Auction proceeds payable	60.7
Trade and other liabilities	261.3
Current operating lease liability	78.1
Income taxes payable	6.0
Long-term operating lease liability	1,166.1
Other non-current liabilities	30.3
Deferred tax liabilities	690.7
Fair value of identifiable net assets acquired	3,115.1
Goodwill acquired on acquisition	$ 3,531.1
VeriTread
Business Acquisition [Line Items]
Total cash consideration paid			$ 28.1
Fair value of previously held interest			4.3
Total fair value of consideration transferred			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