Financing (Tables)

3 Months Ended

Mar. 31, 2026

Debt Disclosure [Abstract]

Schedule of Credit Arrangements

At March 31, 2026, committed credit arrangements with banks were as follows:

	Expires
Company	2026		2028		2029		2030		2031		Total		Unused		Expires within One Year
	(in millions)
Southern Company parent(a)	$	—	$	500	$	—	$	—	$	2,500	$	3,000	$	2,999	$	—
Alabama Power(b)	15		—		650		700		—		1,365		1,365		15
Georgia Power(c)	—		—		—		—		2,050		2,050		2,042		—
Mississippi Power(a)	—		—		125		—		150		275		275		—
Southern Power(a)(d)	—		—		—		—		600		600		600		—
Southern Company Gas(e)	—		—		—		1,600		—		1,600		1,598		—
SEGCO	30		—		—		—		—		30		30		30
Southern Company	$	45	$	500	$	775	$	2,300	$	5,300	$	8,920	$	8,909	$	45

(a)Arrangement expiring in 2031 represents a $3.25 billion combined arrangement for Southern Company, Mississippi Power, and Southern Power allowing for flexible sublimits. Pursuant to the combined facility, the allocations among Southern Company, Mississippi Power, and Southern Power may be adjusted.

(b)Includes $15 million expiring in 2026 at Alabama Property Company, a wholly-owned subsidiary of Alabama Power, of which $15 million was unused at March 31, 2026. Alabama Power is not party to this arrangement.

(c)Georgia Power had $26 million of letters of credit outstanding under an uncommitted letter of credit facility at March 31, 2026.

(d)Does not include Southern Power Company's $75 million and $100 million continuing letter of credit facilities for standby letters of credit, expiring in 2027 and 2028, respectively, of which $17 million and $4 million, respectively, was unused at March 31, 2026. In addition, Southern Power Company had $23 million of letters of credit outstanding under an uncommitted letter of credit facility at March 31, 2026. Southern Power's subsidiaries are not parties to its bank credit arrangements or letter of credit facilities.

(e)Southern Company Gas, as the parent entity, guarantees the obligations of Southern Company Gas Capital, which is the borrower of $800 million of the credit arrangement expiring in 2030. Southern Company Gas' committed credit arrangement expiring in 2030 also includes $800 million for which Nicor Gas is the borrower and which is restricted for working capital needs of Nicor Gas. Pursuant to the multi-year credit arrangement expiring in 2030, the allocations between Southern Company Gas Capital and Nicor Gas may be adjusted.

Schedule of Forward Contracts Indexed to Issuer's Equity

The table below reflects shares of Southern Company common stock sold and settled under separate forward sale contracts with forward purchasers during the three months ended March 31, 2026.

Shares Sold	Initial Forward Price per Share	To be Settled On or Before	Forward Price Per Share Settled	Shares Issued to Settle	Settlement Date
Sold during 2025
3,255,866	$89.4692	December 31, 2026	$89.2443	3,255,866	March 2, 2026
2,314,487	$92.7805	June 30, 2027	$92.8723	2,314,487	March 2, 2026
Sold during 2026
1,467,305	$96.3883	March 31, 2028	N/A	N/A	N/A
1,896,549	$97.5815	March 31, 2028	N/A	N/A	N/A
1,903,317	$95.5086	March 31, 2028	N/A	N/A	N/A

Schedule of Shares Used to Compute Diluted Earnings Per Share

Shares used to compute diluted EPS were as follows:

	Three Months Ended March 31,
	2026	2025
	(in millions)
As reported shares	1,124	1,100
Effect of stock-based compensation	4	5
Diluted shares	1,128	1,105