Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating Activities:
Net income	$ 1,482	$ 1,461
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	1,949	1,916
Deferred income taxes	(101)	(218)
Utilization of federal investment tax credits	224	0
Allowance for equity funds used during construction	(90)	(68)
Mark-to-market adjustments	136	36
Pension, postretirement, and other employee benefits	(115)	(119)
Settlement of asset retirement obligations	(228)	(193)
Stock based compensation expense	105	84
Estimated loss on Plant Vogtle Units 3 and 4	508	149
Storm damage accruals	112	117
Impairment charges	89	154
Natural gas cost under recovery – long-term	(119)	0
Other, net	(60)	(96)
Changes in certain current assets and liabilities —
-Receivables	29	292
-Prepayments	(79)	(102)
-Natural gas for sale, net of temporary LIFO liquidation	375	182
-Natural gas cost under recovery	(485)	0
-Other current assets	36	(253)
-Accounts payable	(177)	(467)
-Accrued taxes	(157)	258
-Accrued compensation	(238)	(347)
-Retail fuel cost over recovery	(146)	174
-Customer refunds	(59)	(223)
-Other current liabilities	(177)	42
Net cash provided from operating activities	2,904	2,847
Investing Activities:
Business acquisitions, net of cash acquired	(345)	(81)
Property additions	(3,384)	(3,202)
Nuclear decommissioning trust fund purchases	(930)	(524)
Nuclear decommissioning trust fund sales	926	519
Proceeds from dispositions	25	983
Cost of removal, net of salvage	(184)	(130)
Change in construction payables, net	(55)	(103)
Payments pursuant to LTSAs	(114)	(91)
Other investing activities	35	(26)
Net cash used for investing activities	(4,026)	(2,655)
Financing Activities:
Increase in notes payable	492
Decrease in notes payable		(1,170)
Proceeds —
Long-term debt	4,646	4,293
Common stock	24	59
Short-term borrowings	325	615
Redemptions and repurchases —
Long-term debt	(2,477)	(2,444)
Short-term borrowings	(25)	(190)
Capital contributions from noncontrolling interests	343	172
Distributions to noncontrolling interests	(113)	(118)
Payment of common stock dividends	(1,377)	(1,332)
Other financing activities	(167)	(170)
Net cash provided from (used for) financing activities	1,671	(285)
Net Change in Cash, Cash Equivalents, and Restricted Cash	549	(93)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	1,068	1,978
Cash, Cash Equivalents, and Restricted Cash at End of Period	1,617	1,885
Cash paid (received) during the period for —
Interest, net of amounts capitalized	884	852
Income taxes, net	88	(8)
Noncash transactions —
Accrued property additions at end of period	943	828
Contributions from noncontrolling interests	89	9
Contributions of wind turbine equipment	82	17
Right-of-use assets obtained under finance leases	90	94
Interest capitalized	43	41
ALABAMA POWER CO
Operating Activities:
Net income	697	585
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	496	484
Deferred income taxes	87	38
Allowance for equity funds used during construction	(24)	(22)
Pension, postretirement, and other employee benefits	(39)	(50)
Settlement of asset retirement obligations	(104)	(100)
Other, net	(35)	24
Changes in certain current assets and liabilities —
-Receivables	(85)	6
-Fossil fuel stock	21	(38)
-Prepayments	(53)	(62)
-Materials and supplies	(7)	(38)
-Other current assets	(37)	(34)
-Accounts payable	(236)	(232)
-Accrued taxes	20	197
-Accrued compensation	(60)	(75)
-Retail fuel cost over recovery	(18)	66
-Other current liabilities	(63)	(97)
Net cash provided from operating activities	584	674
Investing Activities:
Property additions	(844)	(686)
Nuclear decommissioning trust fund purchases	(473)	(160)
Nuclear decommissioning trust fund sales	473	160
Cost of removal, net of salvage	(56)	(29)
Change in construction payables, net	25	(53)
Other investing activities	(18)	(15)
Net cash used for investing activities	(893)	(783)
Proceeds —
Senior notes	600	0
Pollution control revenue bonds	0	87
Redemptions and repurchases —
Pollution control revenue bonds	0	(87)
Senior notes	(200)	0
Capital contributions from parent company	624	610
Payment of common stock dividends	(492)	(479)
Other financing activities	(26)	(15)
Net cash provided from (used for) financing activities	506	116
Net Change in Cash, Cash Equivalents, and Restricted Cash	197	7
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	530	894
Cash, Cash Equivalents, and Restricted Cash at End of Period	727	901
Cash paid (received) during the period for —
Interest, net of amounts capitalized	154	161
Income taxes, net	171	0
Noncash transactions —
Accrued property additions at end of period	191	147
Right-of-use assets obtained under leases	2	3
Interest capitalized	7	7
GEORGIA POWER CO
Operating Activities:
Net income	494	638
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	772	800
Deferred income taxes	(309)	(202)
Allowance for equity funds used during construction	(61)	(40)
Pension, postretirement, and other employee benefits	(59)	(55)
Settlement of asset retirement obligations	(100)	(78)
Estimated loss on Plant Vogtle Units 3 and 4	508	149
Storm damage accruals	107	107
Other, net	90	19
Changes in certain current assets and liabilities —
-Receivables	(73)	(73)
-Fossil fuel stock	55	(52)
-Materials and supplies	(46)	(61)
-Other current assets	15	(26)
-Accounts payable	83	0
-Accrued taxes	14	87
-Accrued compensation	(39)	(69)
-Retail fuel cost over recovery	(113)	109
-Customer refunds	(6)	(159)
-Other current liabilities	(19)	30
Net cash provided from operating activities	1,313	1,124
Investing Activities:
Property additions	(1,575)	(1,650)
Nuclear decommissioning trust fund purchases	(458)	(365)
Nuclear decommissioning trust fund sales	453	359
Proceeds from dispositions	3	143
Cost of removal, net of salvage	(73)	(62)
Change in construction payables, net	(72)	(48)
Other investing activities	(8)	(36)
Net cash used for investing activities	(1,730)	(1,659)
Financing Activities:
Increase in notes payable	250
Decrease in notes payable		(25)
Proceeds —
Senior notes	750	1,500
Pollution control revenue bonds	0	53
FFB loan	371	519
Short-term borrowings	0	250
Redemptions and repurchases —
Pollution control revenue bonds	(69)	(148)
Senior notes	(325)	(950)
FFB loan	(45)	(32)
Capital contributions from parent company	368	500
Payment of common stock dividends	(824)	(771)
Other financing activities	(19)	(27)
Net cash provided from (used for) financing activities	457	869
Net Change in Cash, Cash Equivalents, and Restricted Cash	40	334
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	9	52
Cash, Cash Equivalents, and Restricted Cash at End of Period	49	386
Cash paid (received) during the period for —
Interest, net of amounts capitalized	182	180
Income taxes, net	139	0
Noncash transactions —
Accrued property additions at end of period	476	478
Right-of-use assets obtained under operating leases	3	29
Interest capitalized	30	22
MISSISSIPPI POWER CO
Operating Activities:
Net income	83	71
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	106	92
Settlement of asset retirement obligations	(12)	(9)
Other, net	(16)	(4)
Changes in certain current assets and liabilities —
-Other current assets	(3)	(13)
-Accounts payable	(33)	(19)
-Accrued taxes	(51)	(21)
-Accrued compensation	(10)	(15)
-Retail fuel cost over recovery	(15)	(1)
-Other current liabilities	(8)	(10)
Net cash provided from operating activities	41	71
Investing Activities:
Property additions	(90)	(111)
Change in construction payables, net	(3)	(14)
Payments pursuant to LTSAs	(14)	(10)
Other investing activities	(10)	(10)
Net cash used for investing activities	(117)	(145)
Financing Activities:
Increase in notes payable		4
Decrease in notes payable	(25)
Proceeds —
Senior notes	525	0
Pollution control revenue bonds	0	34
Short-term borrowings	0	40
Other long-term debt	0	100
Redemptions and repurchases —
Short-term borrowings	0	(40)
Pollution control revenue bonds	0	(41)
Senior notes	0	(275)
Capital contributions from parent company	101	75
Return of capital to parent company	0	(74)
Payment of common stock dividends	(79)	0
Other financing activities	(7)	(1)
Net cash provided from (used for) financing activities	515	(178)
Net Change in Cash, Cash Equivalents, and Restricted Cash	439	(252)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	39	286
Cash, Cash Equivalents, and Restricted Cash at End of Period	478	34
Cash paid (received) during the period for —
Interest, net of amounts capitalized	31	33
Income taxes, net	7	0
Noncash transactions —
Accrued property additions at end of period	31	21
Interest capitalized	0	0
SOUTHERN POWER CO
Operating Activities:
Net income	100	112
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	264	251
Deferred income taxes	(20)	(34)
Utilization of federal investment tax credits	205	0
Amortization of investment tax credits	(29)	(30)
(Gain) loss on dispositions, net	(39)	(39)
Other, net	(18)	(31)
Changes in certain current assets and liabilities —
-Receivables	(91)	(67)
-Prepaid income taxes	28	73
-Other current assets	2	(8)
-Accounts payable	14	(29)
-Accrued taxes	8	16
-Other current liabilities	(13)	(19)
Net cash provided from operating activities	411	195
Investing Activities:
Business acquisitions, net of cash acquired	(345)	(81)
Property additions	(224)	(101)
Proceeds from dispositions	17	660
Change in construction payables, net	(14)	(4)
Payments pursuant to LTSAs	(47)	(31)
Other investing activities	12	47
Net cash used for investing activities	(601)	490
Financing Activities:
Decrease in notes payable	(56)	(357)
Proceeds —
Senior notes	400	0
Redemptions and repurchases —
Short-term borrowings	0	(100)
Senior notes	0	(300)
Return of capital to parent company	(271)	0
Capital contributions from noncontrolling interests	343	172
Distributions to noncontrolling interests	(113)	(118)
Payment of common stock dividends	(102)	(100)
Other financing activities	(5)	(5)
Net cash provided from (used for) financing activities	196	(808)
Net Change in Cash, Cash Equivalents, and Restricted Cash	6	(123)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	183	279
Cash, Cash Equivalents, and Restricted Cash at End of Period	189	156
Cash paid (received) during the period for —
Interest, net of amounts capitalized	91	96
Income taxes, net	(189)	(5)
Noncash transactions —
Accrued property additions at end of period	59	38
Contributions from noncontrolling interests	89	9
Contributions of wind turbine equipment	82	17
Right-of-use assets obtained under operating leases	65	30
Interest capitalized	2	7
SOUTHERN Co GAS
Operating Activities:
Net income	333	346
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	263	243
Deferred income taxes	110	40
Mark-to-market adjustments	137	34
Impairment of PennEast Pipeline investment	82	0
Natural gas cost under recovery – long-term	(119)	0
Other, net	15	11
Changes in certain current assets and liabilities —
-Receivables	262	344
-Prepaid income taxes	(129)	14
-Natural gas for sale, net of temporary LIFO liquidation	375	182
-Natural gas cost under recovery	(485)	0
-Other current assets	7	(8)
-Accounts payable	(42)	(176)
-Accrued compensation	17	(31)
-Other current liabilities	(104)	47
Net cash provided from operating activities	722	1,046
Investing Activities:
Property additions	(635)	(647)
Proceeds from dispositions	0	178
Cost of removal, net of salvage	(44)	(31)
Investment in unconsolidated subsidiaries	(3)	(78)
Other investing activities	14	8
Net cash used for investing activities	(668)	(570)
Financing Activities:
Increase in notes payable	210
Decrease in notes payable		(321)
Proceeds —
Short-term borrowings	300	0
Redemptions and repurchases —
Senior notes	(300)	0
Medium-term notes	(30)	0
Capital contributions from parent company	60	186
Payment of common stock dividends	(265)	(266)
Net cash provided from (used for) financing activities	(25)	(401)
Net Change in Cash, Cash Equivalents, and Restricted Cash	29	75
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	19	49
Cash, Cash Equivalents, and Restricted Cash at End of Period	48	124
Cash paid (received) during the period for —
Interest, net of amounts capitalized	127	119
Income taxes, net	100	(4)
Noncash transactions —
Accrued property additions at end of period	137	123
Interest capitalized	$ 3	$ 4