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, 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)
Other	0		2
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
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)
Other	0		2
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)
Other	(1)		(2)	2	0
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 Dec. 31, 2023							31
Beginning balance at Dec. 31, 2023	35,225	5,423	13,775	12,482	(177)	12,333	$ 1,222	7,125	3,993	(7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income						333			333
Capital contributions from parent company						427		427
Other comprehensive income	37				37
Cash dividends on common stock	(766)			(766)		(295)			(295)
Other	7		10	(1)		(1)			(1)
Ending balance (in shares) at Mar. 31, 2024							31
Ending balance at Mar. 31, 2024	35,614	5,431	13,846	12,844	(140)	12,797	$ 1,222	7,552	4,030	(7)
Beginning balance (in shares) at Dec. 31, 2023							31
Beginning balance at Dec. 31, 2023	35,225	5,423	13,775	12,482	(177)	12,333	$ 1,222	7,125	3,993	(7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,867
Ending balance (in shares) at Sep. 30, 2024							31
Ending balance at Sep. 30, 2024	36,905	5,441	14,048	14,005	(139)	13,135	$ 1,222	7,618	4,301	(6)
Beginning balance (in shares) at Mar. 31, 2024							31
Beginning balance at Mar. 31, 2024	35,614	$ 5,431	13,846	12,844	(140)	12,797	$ 1,222	7,552	4,030	(7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income						369			369
Capital contributions from parent company						50		50
Other comprehensive income	10				10	1				1
Cash dividends on common stock	(788)			(788)		(296)			(296)
Other (in shares)		0
Other	1	$ 0	3	0	0
Ending balance (in shares) at Jun. 30, 2024							31
Ending balance at Jun. 30, 2024	36,111	$ 5,436	13,947	13,259	(130)	12,921	$ 1,222	7,602	4,103	(6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,535					493			493
Capital contributions from parent company						16		16
Other comprehensive income	(9)				(9)
Cash dividends on common stock	(789)			(789)		(295)			(295)
Other (in shares)		0
Other	4	$ 0	(2)	0	0
Ending balance (in shares) at Sep. 30, 2024							31
Ending balance at Sep. 30, 2024	$ 36,905	$ 5,441	$ 14,048	$ 14,005	$ (139)	$ 13,135	$ 1,222	$ 7,618	$ 4,301	$ (6)