Asset Retirement Obligations (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2022	Sep. 30, 2022
Asset Retirement Obligations
Asset Retirement Obligation, Period Increase (Decrease)	$ (7)
Amortization and Depreciation of Decontaminating and Decommissioning Assets	47
Asset Retirement Obligation, Beginning Balance	7,162
Settlements	(68)
Asset Retirement Obligation, Revision of Estimate	2
Accretion (recorded as regulatory asset)	59
Asset Retirement Obligation, Ending Balance	7,155
Current portion of ARO	(287)	$ (275)
Nuclear
Asset Retirement Obligations
Asset Retirement Obligation, Beginning Balance	3,643
Settlements	0
Asset Retirement Obligation, Revision of Estimate	3
Accretion (recorded as regulatory asset)	41
Asset Retirement Obligation, Ending Balance	3,687
Non-nuclear
Asset Retirement Obligations
Asset Retirement Obligation, Beginning Balance	3,519
Settlements	(68)
Asset Retirement Obligation, Revision of Estimate	(1)
Accretion (recorded as regulatory asset)	18
Asset Retirement Obligation, Ending Balance	3,468
Accounts payable and accrued liabilities
Asset Retirement Obligations
Settlements	$ (57)

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

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- Definition

Reconciliation of Asset Retirement Obligations [Line Items]

+ References

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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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

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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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 25
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=116646717&loc=d3e6290-110844

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

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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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

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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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(2)
-URI https://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

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- Definition

Amount of increase (decrease) in asset retirement obligations.

+ References

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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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(4)
-URI https://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

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