XML 172 R149.htm IDEA: XBRL DOCUMENT v3.25.4

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	1 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Nov. 29, 2023
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Proposed annual rate	0.0297%			0.0336%
Accrual for special assessment charge	$ 5.9	$ 10.3	$ 47.2
Special deposit insurance assessment accrual released	10.3
SEC Schedule, 12-09, Allowance, Credit Loss
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
ACL on unfunded loan commitments	$ 24.1	$ 22.6

X

- 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/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 09
-Paragraph Column E
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 09
-Paragraph Column D
-Publisher SEC

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 09
-Paragraph Column C
-Subparagraph (1)
-Publisher SEC

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 09
-Paragraph Column C
-Subparagraph (2)
-Publisher SEC

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 09
-Paragraph Column B
-Publisher SEC

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-5

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09(Column C)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-4

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09(Column C)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-4

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09(Column B))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-4

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09(Column E))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-4

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09(Column D))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-4

+ Details

Name:	srt_ValuationAndQualifyingAccountsDisclosureLineItems
Namespace Prefix:	srt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of valuation and qualifying accounts and reserves.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-5

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09(Column B))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-4

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09(Column E))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-4

+ Details

Name:	us-gaap_ValuationAllowancesAndReservesBalance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Deposit Liability, Uninsured, Proposed Annual Rate

+ References

No definition available.

+ Details

Name:	wbs_DepositLiabilityUninsuredProposedAnnualRate
Namespace Prefix:	wbs_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Estimated Special Assessment Charge

+ References

No definition available.

+ Details

Name:	wbs_EstimatedSpecialAssessmentCharge
Namespace Prefix:	wbs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Released Special Assessment Accrual

+ References

No definition available.

+ Details

Name:	wbs_ReleasedSpecialAssessmentAccrual
Namespace Prefix:	wbs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=us-gaap_AllowanceForCreditLossMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: