Consolidated Statements of Comprehensive (Loss) Income (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Statement of Comprehensive Income [Abstract]
Net derivative gains and other costs arising during the period, net of tax expense (benefit)	$ 0.4	$ 0.7	$ 0.4	$ 1.1
Reclassification of losses (gains) into net (loss), net of tax (expense) benefit	$ (0.4)	$ 0.2	$ (1.0)	$ 0.0

Amount of tax expense (benefit) for reclassification adjustment from accumulated other comprehensive income (loss) for unrealized gain (loss) from increase (decrease) in instrument-specific credit risk, realized upon derecognition of financial liability measured under fair value option.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (d)(4)
-URI https://asc.fasb.org/extlink&oid=123596393&loc=d3e14172-108612

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI https://asc.fasb.org/extlink&oid=126968391&loc=d3e640-108580

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (l)
-URI https://asc.fasb.org/extlink&oid=126968391&loc=SL7669646-108580

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