Asset Retirement Obligations (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2023	Sep. 30, 2023
Asset Retirement Obligations
Asset Retirement Obligation, Period Increase (Decrease)	$ 81
Amortization and Depreciation of Decontaminating and Decommissioning Assets	47
Asset Retirement Obligation, Beginning Balance	7,489
Settlements	(63)
Asset Retirement Obligation, Revision of Estimate	78
Accretion (recorded as regulatory asset)	66
Asset Retirement Obligation, Ending Balance	7,570
Current portion of ARO	(275)	$ (272)
Changes in closure liabilities	76
Nuclear
Asset Retirement Obligations
Asset Retirement Obligation, Beginning Balance	3,808
Settlements	(4)
Asset Retirement Obligation, Revision of Estimate	0
Accretion Expense, Including Asset Retirement Obligations	43
Asset Retirement Obligation, Ending Balance	3,847
Non-nuclear
Asset Retirement Obligations
Asset Retirement Obligation, Beginning Balance	3,681
Settlements	(59)
Asset Retirement Obligation, Revision of Estimate	78
Accretion (recorded as regulatory asset)	23
Asset Retirement Obligation, Ending Balance	$ 3,723

The amount of accretion recorded as a regulatory asset during the period.

No definition available.

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- Definition

Changes in closure liabilities

+ References

No definition available.

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- Definition

Reconciliation of Asset Retirement Obligations [Line Items]

+ References

No definition available.

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- Definition

Amount of accretion expense, which includes, but is not limited to, accretion expense from asset retirement obligations, environmental remediation obligations, and other contingencies.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 410
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481879/410-20-45-1

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- Definition

The current period expense charged against earnings on decontaminating and decommissioning of facilities used in the normal conduct of business and not intended for resale to allocate or recognize the cost of the assets over their useful lives.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-28

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- Definition

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 410
-SubTopic 20
-Name Accounting Standards Codification
-Section 25
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481999/410-20-25-4

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 410
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481850/410-20-50-1

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- Definition

Current portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 410
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481850/410-20-50-1

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- Definition

Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 410
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481850/410-20-50-1

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- Definition

Amount of increase (decrease) in asset retirement obligations.

+ References

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- Definition

Amount of increase (decrease) in the asset retirement obligation from changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 410
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481850/410-20-50-1

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