Condensed Statements of Comprehensive Income - MPC (Parenthetical) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Changes in fair value, tax	$ (5)	$ (1)	$ 12	$ (2)
Mississippi Power
Changes in fair value, tax	$ 0	$ 0	$ 0	$ 2

Amount, before reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482790/220-10-45-12

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration