Condensed Statements of Common Stockholders' Equity (Unaudited) - APC - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-In Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Alabama Power	Alabama Power Common Stock	Alabama Power Paid-In Capital	Alabama Power Retained Earnings (Accumulated Deficit)	Alabama Power Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2021							31
Beginning balance at Dec. 31, 2021	$ 32,276	$ 5,279	$ 11,950	$ 10,929	$ (237)	$ 10,713	$ 1,222	$ 6,056	$ 3,448	$ (13)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income						347			347
Capital contributions from parent company						626		626
Other comprehensive income	42				42
Cash dividends on common stock	(702)			(702)		(254)			(254)
Ending balance (in shares) at Mar. 31, 2022							31
Ending balance at Mar. 31, 2022	32,629	5,286	11,994	11,261	(195)	11,432	$ 1,222	6,682	3,541	(13)
Beginning balance (in shares) at Dec. 31, 2021							31
Beginning balance at Dec. 31, 2021	32,276	5,279	11,950	10,929	(237)	10,713	$ 1,222	6,056	3,448	(13)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	3,611					1,256
Ending balance (in shares) at Sep. 30, 2022							31
Ending balance at Sep. 30, 2022	35,476	5,417	13,657	12,374	(157)	11,874	$ 1,222	6,721	3,941	(10)
Beginning balance (in shares) at Mar. 31, 2022							31
Beginning balance at Mar. 31, 2022	32,629	5,286	11,994	11,261	(195)	11,432	$ 1,222	6,682	3,541	(13)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income						383			383
Capital contributions from parent company						32		32
Other comprehensive income	11				11	1				1
Cash dividends on common stock	(723)			(723)		(254)			(254)
Ending balance (in shares) at Jun. 30, 2022							31
Ending balance at Jun. 30, 2022	33,013	5,288	12,033	11,645	(184)	11,594	$ 1,222	6,714	3,670	(12)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,472					525			525
Capital contributions from parent company						7		7
Other comprehensive income	28				28	2				2
Cash dividends on common stock	(741)			(741)		(254)			(254)
Ending balance (in shares) at Sep. 30, 2022							31
Ending balance at Sep. 30, 2022	35,476	5,417	13,657	12,374	(157)	11,874	$ 1,222	6,721	3,941	(10)
Beginning balance (in shares) at Dec. 31, 2022							31
Beginning balance at Dec. 31, 2022	34,532	5,417	13,673	11,538	(167)	11,687	$ 1,222	6,710	3,764	(9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income						255			255
Capital contributions from parent company						330		330
Other comprehensive income	(44)				(44)
Cash dividends on common stock	(742)			(742)		(285)			(285)
Ending balance (in shares) at Mar. 31, 2023							31
Ending balance at Mar. 31, 2023	34,562	5,421	13,715	11,658	(211)	11,987	$ 1,222	7,040	3,734	(9)
Beginning balance (in shares) at Dec. 31, 2022							31
Beginning balance at Dec. 31, 2022	34,532	5,417	13,673	11,538	(167)	11,687	$ 1,222	6,710	3,764	(9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	3,121					1,132
Ending balance (in shares) at Sep. 30, 2023							31
Ending balance at Sep. 30, 2023	35,304	5,422	13,751	12,391	(130)	12,351	$ 1,222	7,097	4,040	(8)
Beginning balance (in shares) at Mar. 31, 2023							31
Beginning balance at Mar. 31, 2023	34,562	5,421	13,715	11,658	(211)	11,987	$ 1,222	7,040	3,734	(9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income						312			312
Capital contributions from parent company						29		29
Other comprehensive income	43				43
Cash dividends on common stock	(764)			(764)		(286)			(286)
Ending balance (in shares) at Jun. 30, 2023							31
Ending balance at Jun. 30, 2023	34,648	5,422	13,742	11,732	(168)	12,042	$ 1,222	7,069	3,760	(9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,422					565			565
Capital contributions from parent company						28		28
Other comprehensive income	38				38	1				1
Cash dividends on common stock	(765)			(765)		(285)			(285)
Ending balance (in shares) at Sep. 30, 2023							31
Ending balance at Sep. 30, 2023	$ 35,304	$ 5,422	$ 13,751	$ 12,391	$ (130)	$ 12,351	$ 1,222	$ 7,097	$ 4,040	$ (8)