Discontinued Operations - Schedule of Assets and Liabilities Held-for-Sale (Details) - USD ($) $ in Millions		Jun. 30, 2023	Dec. 31, 2022
Current assets:
Current assets held-for-sale	[1]	$ 108.8	$ 107.2
Current liabilities:
Current liabilities held-for-sale	[1]	42.3	43.8
Disposal Group, Held-for-sale, Not Discontinued Operations | Aluminum Products Business
Current assets:
Accounts receivable, net		31.0	24.9
Inventories, net		24.4	30.2
Other current assets		1.9	1.2
Current assets held-for-sale		57.3	56.3
Property, plant and equipment, net		47.8	46.1
Operating lease right-of-use assets		3.7	4.8
Long-term assets held-for-sale		51.5	50.9
Total assets held-for-sale		108.8	107.2
Current liabilities:
Trade accounts payable		25.3	22.8
Current portion of finance lease liabilities		2.0	2.4
Current portion of operating lease liabilities		1.8	2.3
Other accrued expenses		9.0	10.7
Current liabilities held-for-sale		38.1	38.2
Long-term finance lease liabilities		2.3	3.1
Long-term operating lease liabilities		1.9	2.5
Long-term liabilities held-for-sale		4.2	5.6
Total liabilities held-for-sale		$ 42.3	$ 43.8

[1] Our continuing operations exclude the results of our Aluminum Products business unit, which is held-for-sale as of June 30, 2023 and December 31, 2022 and presented in discontinued operations for all periods presented.