Condensed Statements of Common Stockholders' Equity (Unaudited) - MPC - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-In Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Mississippi Power	Mississippi Power Common Stock	Mississippi Power Paid-In Capital	Mississippi Power Retained Earnings (Accumulated Deficit)	Mississippi Power Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2022							1
Beginning balance at Dec. 31, 2022	$ 34,532	$ 5,417	$ 13,673	$ 11,538	$ (167)	$ 1,931	$ 38	$ 4,652	$ (2,759)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	799					58			58
Other comprehensive income (loss)	(44)				(44)
Cash dividends on common stock	(742)			(742)		(46)			(46)
Ending balance (in shares) at Mar. 31, 2023							1
Ending balance at Mar. 31, 2023	34,562	5,421	13,715	11,658	(211)	1,943	$ 38	4,652	(2,747)	0
Beginning balance (in shares) at Dec. 31, 2023							1
Beginning balance at Dec. 31, 2023	35,225	5,423	13,775	12,482	(177)	2,003	$ 38	4,721	(2,756)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,071					50			50
Capital contributions from parent company						1		1
Other comprehensive income (loss)	37				37	5				5
Cash dividends on common stock	(766)			(766)		(47)			(47)
Ending balance (in shares) at Mar. 31, 2024							1
Ending balance at Mar. 31, 2024	$ 35,614	$ 5,431	$ 13,846	$ 12,844	$ (140)	$ 2,012	$ 38	$ 4,722	$ (2,753)	$ 5