Statements of Common Stockholders' Equity - MPC - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Mississippi Power	Mississippi Power Common Stock	Mississippi Power Paid-In Capital	Mississippi Power Retained Earnings	Mississippi Power Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2019		1,054					1
Beginning balance at Dec. 31, 2019	$ 31,759	$ 5,257	$ 11,734	$ 10,877	$ (321)	$ 1,652	$ 38	$ 4,449	$ (2,832)	$ (3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated Net Income	3,119					152			152
Return of capital to parent company						(74)		(74)
Capital contributions from parent company						86		86
Other comprehensive income (loss)	(75)				(75)	1				1
Cash dividends on common stock	(2,685)			(2,685)		(74)			(74)
Other	(12)		(10)		(1)	(1)		(1)
Ending balance (in shares) at Dec. 31, 2020		1,058					1
Ending 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]
Consolidated Net Income	2,393					159			159
Capital contributions from parent company						122		122
Other comprehensive income (loss)	158				158	1				1
Cash dividends on common stock	(2,777)			(2,777)		(157)			(157)
Other	(7)		(8)	2		0			1	(1)
Ending balance (in shares) at Dec. 31, 2021		1,061					1
Ending 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]
Consolidated Net Income	3,524					164			164
Capital contributions from parent company						70		70
Other comprehensive income (loss)	71				71
Cash dividends on common stock	(2,907)			(2,907)		(170)			(170)
Other	(6)		9	(8)	(1)
Ending balance (in shares) at Dec. 31, 2022		1,090					1
Ending balance at Dec. 31, 2022	$ 34,532	$ 5,417	$ 13,673	$ 11,538	$ (167)	$ 1,931	$ 38	$ 4,652	$ (2,759)	$ 0