Fair value of credit risk derivative asset after deduction of credit risk derivative liability.

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

+ Details

Name:	us-gaap_CreditRiskDerivativesAtFairValueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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

+ Details

Name:	us-gaap_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Proceeds From (Payments For) Derivative Instrument, Operating Activities

+ References

No definition available.

+ Details

Name:	vg_ProceedsFromPaymentsForDerivativeInstrumentOperatingActivities
Namespace Prefix:	vg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=vg_DerivativeSettlementTrancheOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CommodityContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Derivatives - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
Derivatives - Narrative (Details) - USD ($) $ in Millions	Apr. 30, 2025	Sep. 30, 2025	Sep. 30, 2024
Derivative [Line Items]
Proceeds from settlement of interest rate swap	$ 869	$ 994	$ 160
Derivative settlement, tranche one
Derivative [Line Items]
Proceeds from settlement of interest rate swap		869
Interest rate swaps
Derivative [Line Items]
Fair value of credit-risk derivative, net liability		259
Natural gas supply contracts
Derivative [Line Items]
Fair value of credit-risk derivative, net liability		$ 62