Regulatory - Schedule of Regulatory Assets and Regulatory Liabilities (Detail) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Regulatory assets:
Regulatory assets	$ 1,376	$ 1,441
Less: Current portion	390	343
Long-term regulatory assets	986	1,098
Regulatory liabilities:
Regulatory liabilities	842	904
Less: Current portion	101	146
Long-term regulatory liabilities	741	758
Regulatory Tax Liability [Member] \| Non-Current Liabilities [Member]
Regulatory liabilities:
Regulatory liabilities	446	456
Cost-recovery Clauses - Deferred Balances [Member]
Regulatory liabilities:
Regulatory liabilities	24	80
Accumulated Reserve - Cost of Removal [Member]
Regulatory liabilities:
Regulatory liabilities	299	304
Deferred production tax credits [Member]
Regulatory liabilities:
Regulatory liabilities	48	57
Other [Member]
Regulatory liabilities:
Regulatory liabilities	25	7
Regulatory Tax Asset [Member]
Regulatory assets:
Regulatory assets	125	117
Cost-Recovery Clauses [Member]
Regulatory assets:
Regulatory assets	36	20
Capital Cost Recovery for Early Retired Assets [Member]
Regulatory assets:
Regulatory assets	520	513
Capital cost recovery for retired Polk Unit 1 components
Regulatory assets:
Regulatory assets	136	142
Postretirement Benefits [Member]
Regulatory assets:
Regulatory assets	240	243
Storm Reserve [Member]
Regulatory assets:
Regulatory assets	285	377
Other [Member]
Regulatory assets:
Regulatory assets	$ 34	$ 29

Regulatory assets.

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Regulatory liabilities.

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The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 340
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478742/980-340-50-1

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Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are expected to be recovered through revenue sources within one year or the normal operating cycle, if longer. Such costs are capitalized if they meet both of the following criteria: a. It is probable that future revenue in an amount at least equal to the capitalized cost will result from inclusion of that cost in allowable costs for rate-making purposes. b. Based on available evidence, the future revenue will be provided to permit recovery of the previously incurred cost rather than to provide for expected levels of similar future costs. If the revenue will be provided through an automatic rate-adjustment clause, this criterion requires that the regulator's intent clearly be to permit recovery of the previously incurred cost.

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Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer.

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The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 405
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477571/980-405-25-1

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The amount for the individual regulatory current liability as itemized in a table of regulatory current liabilities as of the end of the period.

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The amount for the individual regulatory noncurrent liability as itemized in a table of regulatory noncurrent liabilities as of the end of the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(24))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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