Condensed Consolidated Statements of Income (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Operating revenues	$ 5,198	$ 4,620	$ 11,108	$ 9,638
Alternative revenue programs
Operating revenues	2	(2)	4	7
SOUTHERN Co GAS
Operating revenues	677	636	2,371	1,885
Revenue taxes collected	23	22	77	69
SOUTHERN Co GAS | Alternative revenue programs
Operating revenues	$ 2	$ (2)	$ 4	$ 7