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	862					255			255
Capital contributions from parent company						330		330
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, 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	1,129					333			333
Capital contributions from parent company						427		427
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)