Condensed Consolidated Statements of Income (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating revenues	$ 6,238	$ 5,620	$ 17,346	$ 15,258
Alternative revenue programs
Operating revenues	(1)	(1)	3	6
SOUTHERN Co GAS
Operating revenues	623	477	2,994	2,362
Revenue taxes collected	12	10	89	79
SOUTHERN Co GAS | Alternative revenue programs
Operating revenues	$ (1)	$ (1)	$ 3	$ 6