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, 2020							31
Beginning balance at Dec. 31, 2020	$ 32,234	$ 5,268	$ 11,834	$ 11,311	$ (395)	$ 9,810	$ 1,222	$ 5,413	$ 3,194	$ (19)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income after dividends on preferred stock						359			359
Capital contributions from parent company						602		602
Other comprehensive income (loss)	28				28	1				1
Cash dividends on common stock	(678)			(678)		(246)			(246)
Other	1		2
Ending balance (in shares) at Mar. 31, 2021							31
Ending balance at Mar. 31, 2021	33,068	5,273	11,854	11,768	(367)	10,526	$ 1,222	6,015	3,307	(18)
Beginning balance (in shares) at Dec. 31, 2020							31
Beginning balance at Dec. 31, 2020	32,234	5,268	11,834	11,311	(395)	9,810	$ 1,222	5,413	3,194	(19)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income after dividends on preferred stock	1,508					690
Ending balance (in shares) at Jun. 30, 2021							31
Ending balance at Jun. 30, 2021	32,746	5,274	11,886	11,442	(355)	10,637	$ 1,222	6,041	3,391	(17)
Beginning balance (in shares) at Mar. 31, 2021							31
Beginning balance at Mar. 31, 2021	33,068	5,273	11,854	11,768	(367)	10,526	$ 1,222	6,015	3,307	(18)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income after dividends on preferred stock	372					331			331
Capital contributions from parent company						26		26
Other comprehensive income (loss)	12				12	1				1
Cash dividends on common stock	(699)			(699)		(246)			(246)
Other	0		1	1		(1)			(1)
Ending balance (in shares) at Jun. 30, 2021							31
Ending balance at Jun. 30, 2021	32,746	5,274	11,886	11,442	(355)	10,637	$ 1,222	6,041	3,391	(17)
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 after dividends on preferred stock						347			347
Capital contributions from parent company						626		626
Other comprehensive income (loss)	42				42
Cash dividends on common stock	(702)			(702)		(254)			(254)
Other	7		7	2
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 after dividends on preferred stock	2,139					730
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)
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 after dividends on preferred stock	1,107					383			383
Capital contributions from parent company						32		32
Other comprehensive income (loss)	11				11	1				1
Cash dividends on common stock	(723)			(723)		(254)			(254)
Other	2		4
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)