Defined benefit plan non service cost credit.

No definition available.

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- Definition

Defined contribution plan operating expenses within discontinued operations.

+ References

No definition available.

+ Details

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- Definition

Defined contribution plan operating expenses within discontinued operations after tax.

+ References

No definition available.

+ Details

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- Definition

Defined contribution plan other operations and maintenance expense.

+ References

No definition available.

+ Details

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- Definition

Defined contribution plan other operations and maintenance expense after tax.

+ References

No definition available.

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- Definition

Remeasured pension and other postretirement benefit plans after tax amount.

+ References

No definition available.

+ Details

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- Definition

Remeasured pension and other postretirement benefit plans amount.

+ References

No definition available.

+ Details

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- Definition

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (k)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

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- Definition

Amount of contribution expected to be received by defined benefit plan from employer in remainder of current fiscal year. Excludes contribution previously paid by employer in current fiscal year.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480482/715-20-55-18

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-Topic 715
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-Section 50
-Paragraph 6
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-6

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- Definition

Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
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-URI https://asc.fasb.org/1943274/2147480506/715-20-50-6

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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

No definition available.

+ Details

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- Definition

Amount of cash outflow for pension benefit. Includes, but is not limited to, employer contribution to fund plan asset and payment to retiree. Excludes other postretirement benefit.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 25
-Subparagraph (g)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-25

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Employee Benefit Plans (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2025	Jun. 30, 2024
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution plan operating expenses within discontinued operations			$ 23
Defined contribution plan operating expenses within discontinued operations after tax			17
Defined contribution plan other operations and maintenance expense			13
Defined contribution plan other operations and maintenance expense after tax			10
Expected contributions to qualified defined benefit pension plans for remainder of fiscal year	$ 22			$ 22
East Ohio
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Remeasured pension and other postretirement benefit plans amount			202
Remeasured pension and other postretirement benefit plans after tax amount			$ 151
Questar Gas
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Remeasured pension and other postretirement benefit plans amount		$ 15
Remeasured pension and other postretirement benefit plans after tax amount		11
Discontinued Operations
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost		2			$ 5
Non-service cost (credit)		(1)			13
Other Postretirement Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	2	$ 3		5	$ 6
Other Postretirement Benefits Plan \| Questar Gas
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Remeasurement, discount rate		5.74%			5.74%
Other Postretirement Benefits Plan \| Minimum \| East Ohio
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Remeasurement, discount rate			5.61%
Other Postretirement Benefits Plan \| Maximum \| East Ohio
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Remeasurement, discount rate			5.62%
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to qualified defined benefit pension plans	6			7
Service cost	$ 19	$ 22		$ 38	$ 44
Pension Benefits \| East Ohio
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Remeasurement, discount rate			5.62%
Pension Benefits \| Questar Gas
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Remeasurement, discount rate		5.75%			5.75%