Consolidated Statements of Comprehensive Income - Southern - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 2,309	$ 3,103	$ 4,744
Qualifying hedges:
Changes in fair value, net of tax	(49)	10	(115)
Reclassification adjustment for amounts included in net income, net of tax	96	(40)	57
Pension and other postretirement benefit plans:
Benefit plan net gain (loss), net of tax	98	(55)	(64)
Reclassification adjustment for amounts included in net income, net of tax	13	10	4
Total other comprehensive income (loss)	158	(75)	(118)
Dividends on preferred stock of subsidiaries	15	15	15
Comprehensive loss attributable to noncontrolling interests	(99)	(31)	(10)
Comprehensive Income (Loss) Attributable to Parent	$ 2,551	$ 3,044	$ 4,621