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, 2020							1
Beginning balance at Dec. 31, 2020	$ 32,234	$ 5,268	$ 11,834	$ 11,311	$ (395)	$ 1,742	$ 38	$ 4,460	$ (2,754)	$ (2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income						45			45
Capital contributions from parent company						100		100
Cash dividends on common stock	(678)			(678)		(39)			(39)
Other	1		2
Ending balance (in shares) at Mar. 31, 2021							1
Ending balance at Mar. 31, 2021	33,068	5,273	11,854	11,768	(367)	1,848	$ 38	4,560	(2,748)	(2)
Beginning balance (in shares) at Dec. 31, 2020							1
Beginning balance at Dec. 31, 2020	32,234	5,268	11,834	11,311	(395)	1,742	$ 38	4,460	(2,754)	(2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,508
Ending balance (in shares) at Jun. 30, 2021							1
Ending balance at Jun. 30, 2021	32,746	5,274	11,886	11,442	(355)	1,849	$ 38	4,562	(2,750)	(1)
Beginning balance (in shares) at Mar. 31, 2021							1
Beginning balance at Mar. 31, 2021	33,068	5,273	11,854	11,768	(367)	1,848	$ 38	4,560	(2,748)	(2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	372					38			38
Capital contributions from parent company						2		2
Cash dividends on common stock	(699)			(699)		(39)			(39)
Other	0		1	1					(1)	1
Ending balance (in shares) at Jun. 30, 2021							1
Ending balance at Jun. 30, 2021	32,746	5,274	11,886	11,442	(355)	1,849	$ 38	4,562	(2,750)	(1)
Beginning balance (in shares) at Dec. 31, 2021							1
Beginning balance at Dec. 31, 2021	32,276	5,279	11,950	10,929	(237)	1,867	$ 38	4,582	(2,753)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income						42			42
Capital contributions from parent company						51		51
Cash dividends on common stock	(702)			(702)		(43)			(43)
Other	7		7	2
Ending balance (in shares) at Mar. 31, 2022							1
Ending balance at Mar. 31, 2022	32,629	5,286	11,994	11,261	(195)	1,917	$ 38	4,633	(2,754)	0
Beginning balance (in shares) at Dec. 31, 2021							1
Beginning balance at Dec. 31, 2021	32,276	5,279	11,950	10,929	(237)	1,867	$ 38	4,582	(2,753)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,139
Ending balance (in shares) at Jun. 30, 2022							1
Ending balance at Jun. 30, 2022	33,013	5,288	12,033	11,645	(184)	1,921	$ 38	4,634	(2,751)	0
Beginning balance (in shares) at Mar. 31, 2022							1
Beginning balance at Mar. 31, 2022	32,629	5,286	11,994	11,261	(195)	1,917	$ 38	4,633	(2,754)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,107					45			45
Capital contributions from parent company						1		1
Cash dividends on common stock	(723)			(723)		(42)			(42)
Other	2		4
Ending balance (in shares) at Jun. 30, 2022							1
Ending balance at Jun. 30, 2022	$ 33,013	$ 5,288	$ 12,033	$ 11,645	$ (184)	$ 1,921	$ 38	$ 4,634	$ (2,751)	$ 0