Derivatives - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Securities fair value hedges
Derivative [Line Items]
Reclassification of fair value hedge from AOCI into income		$ (2.8)	$ (0.4)	$ (2.0)
Fair value hedge gain (loss) reclassified		0.3	(0.5)	0.3
Residential mortgage fair value hedges
Derivative [Line Items]
Gain (loss) on derivative instruments	$ (0.5)	$ 0.9	$ (0.4)	$ 1.8

Other Comprehensive Income (Loss), Fair Value Hedge, Gain (Loss), Before Reclassification And Tax

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- Definition

Other Comprehensive Income (Loss), Fair Value Hedge, Gain (Loss), Reclassification, Before Tax

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 25
-Paragraph 6A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480682/815-20-25-6A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480237/815-40-50-5

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- Definition

Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-4A

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