Financing (Tables)

3 Months Ended

Mar. 31, 2021

Debt Disclosure [Abstract]

Schedule of Credit Arrangements

At March 31, 2021, committed credit arrangements with banks were as follows:

	Expires
Company	2021		2022		2023		2024		Total		Unused		Due within One Year
	(in millions)
Southern Company parent	$	—	$	—	$	—	$	2,000	$	2,000	$	1,999	$	—
Alabama Power	3		525		—		800		1,328		1,328		3
Georgia Power	—		—		—		1,750		1,750		1,728		—
Mississippi Power	—		150		125		—		275		250		—
Southern Power(a)	—		—		—		600		600		568		—
Southern Company Gas(b)	—		—		—		1,750		1,750		1,745		—
SEGCO	30		—		—		—		30		30		30
Southern Company	$	33	$	675	$	125	$	6,900	$	7,733	$	7,648	$	33

(a)Does not include Southern Power Company's $75 million and $60 million continuing letter of credit facilities for standby letters of credit expiring in 2023, of which $12 million and $1 million, respectively, was unused at March 31, 2021. Southern Power's subsidiaries are not parties to its bank credit arrangements or letter of credit facilities.

(b)Southern Company Gas, as the parent entity, guarantees the obligations of Southern Company Gas Capital, which is the borrower of $1.05 billion of this arrangement. Southern Company Gas' committed credit arrangement also includes $700 million for which Nicor Gas is the borrower and which is restricted for working capital needs of Nicor Gas. Pursuant to this multi-year credit arrangement, the allocations between Southern Company Gas Capital and Nicor Gas may be adjusted.

Schedule of Shares Used to Compute Diluted Earnings Per Share

Shares used to compute diluted earnings per share were as follows:

	Three Months Ended March 31, 2021	Three Months Ended March 31, 2020
	(in millions)
As reported shares	1,060	1,057
Effect of stock-based compensation	6	7
Effect of equity units	—	3
Diluted shares	1,066	1,067