Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Consolidated Net Income	$ 4,744	$ 2,300	$ 926
Qualifying hedges:
Changes in fair value, net of tax	(115)
Changes in fair value, net of tax		(47)	57
Reclassification adjustment for amounts included in net income, net of tax	57
Reclassification adjustment for amounts included in net income, net of tax		72	(60)
Pension and other postretirement benefit plans:
Benefit plan net gain (loss), net of tax	(64)	(5)	17
Reclassification adjustment for amounts included in net income, net of tax	4	6	(23)
Total other comprehensive income (loss)	(118)	26	(9)
Dividends on preferred and preference stock of subsidiaries	15	16	38
Comprehensive income (loss) attributable to noncontrolling interests	(10)	58	46
Current period change	4,621	2,252	833
Alabama Power
Consolidated Net Income	1,085	945	866
Qualifying hedges:
Changes in fair value, net of tax	0
Changes in fair value, net of tax		0	1
Reclassification adjustment for amounts included in net income, net of tax	4
Reclassification adjustment for amounts included in net income, net of tax		4	3
Pension and other postretirement benefit plans:
Total other comprehensive income (loss)	4	4	4
Dividends on preferred and preference stock of subsidiaries	15	15	18
Current period change	1,089	949	870
Georgia Power
Consolidated Net Income	1,720	793	1,428
Qualifying hedges:
Changes in fair value, net of tax	(44)
Changes in fair value, net of tax		0	0
Reclassification adjustment for amounts included in net income, net of tax	2
Reclassification adjustment for amounts included in net income, net of tax		3	3
Pension and other postretirement benefit plans:
Total other comprehensive income (loss)	(42)	3	3
Dividends on preferred and preference stock of subsidiaries	0	0	14
Current period change	1,678	796	1,431
Mississippi Power
Consolidated Net Income	139	236	(2,588)
Qualifying hedges:
Changes in fair value, net of tax	0
Changes in fair value, net of tax		(1)	(1)
Reclassification adjustment for amounts included in net income, net of tax	1
Reclassification adjustment for amounts included in net income, net of tax		1	1
Pension and other postretirement benefit plans:
Total other comprehensive income (loss)	1	0	0
Dividends on preferred and preference stock of subsidiaries	0	1	2
Current period change	140	236	(2,588)
Southern Power
Consolidated Net Income	329	246	1,117
Qualifying hedges:
Changes in fair value, net of tax	(66)
Changes in fair value, net of tax		(51)	63
Reclassification adjustment for amounts included in net income, net of tax	41
Reclassification adjustment for amounts included in net income, net of tax		58	(73)
Pension and other postretirement benefit plans:
Benefit plan net gain (loss), net of tax	(17)	5	0
Reclassification adjustment for amounts included in net income, net of tax	0	2	0
Total other comprehensive income (loss)	(42)	14	(10)
Comprehensive income (loss) attributable to noncontrolling interests	(10)	59	46
Current period change	297	201	1,061
Southern Company Gas
Consolidated Net Income	585	372	243
Qualifying hedges:
Changes in fair value, net of tax	(5)
Changes in fair value, net of tax		5	(5)
Reclassification adjustment for amounts included in net income, net of tax	2
Reclassification adjustment for amounts included in net income, net of tax		(1)	1
Pension and other postretirement benefit plans:
Benefit plan net gain (loss), net of tax	(16)	0	(1)
Reclassification adjustment for amounts included in net income, net of tax	0	(2)	0
Total other comprehensive income (loss)	(19)	2	(5)
Current period change	$ 566	$ 374	$ 238