Divestitures, Discontinued Operations and Assets and Liabilities Held for Sale - Summary of Discontinued Operations (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Discontinued Operations and Disposal Groups [Abstract]
Total revenues	$ 27.2	$ 62.4	$ 86.4	$ 268.8
Pretax earnings (loss) from discontinued operations	3.9	4.7	(14.6)	21.1
Pretax (loss) gain on divestitures and sales of assets	(21.9)	0.7	(19.6)	(0.3)
Pretax (loss) earnings	(18.0)	5.4	(34.2)	20.8
Income tax (benefit) expense	(4.4)	1.3	(8.4)	6.5
(Loss) Earnings from discontinued operations, net of income tax (benefit) expense	$ (13.6)	$ 4.1	$ (25.8)	$ 14.3

Amount before tax of income (loss) from a discontinued operation. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

Amount of tax expense (benefit) related to a discontinued operation. Includes, but is not limited to, tax expense (benefit) related to income (loss) from operations during the phase-out period, tax expense (benefit) related to gain (loss) on disposal, tax expense (benefit) related to gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and tax expense (benefit) related to adjustments of a prior period gain (loss) on disposal.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
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-Paragraph 1
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-URI https://asc.fasb.org//1943274/2147483499/205-20-50-1

+ Details

- Definition

Amount after tax of income (loss) from a discontinued operation attributable to the parent. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

+ References + Details