Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Current Assets:
Cash and cash equivalents	$ 2,078	$ 1,065
Receivables —
Customer accounts	1,831	1,753
Energy marketing	0	516
Unbilled revenues	535	672
Other accounts and notes	611	512
Accumulated provision for uncollectible accounts	(72)	(118)
Materials and supplies	1,504	1,478
Fossil fuel for generation	386	550
Natural gas for sale	368	460
Prepaid expenses	329	276
Assets from risk management activities, net of collateral	365	147
Regulatory assets – asset retirement obligations	233	214
Natural gas cost under recovery	432	0
Other regulatory assets	792	810
Other current assets	282	282
Total current assets	9,674	8,617
Property, Plant, and Equipment:
In service	114,166	110,516
Less: Accumulated depreciation	33,723	32,397
Plant in service, net of depreciation	80,443	78,119
Nuclear fuel, at amortized cost	805	818
Construction work in progress	9,611	8,697
Total property, plant, and equipment	90,859	87,634
Other Property and Investments:
Goodwill	5,280	5,280
Nuclear decommissioning trusts, at fair value	2,446	2,303
Equity investments in unconsolidated subsidiaries	1,278	1,362
Other intangible assets, net of amortization	455	487
Leveraged leases	575	556
Miscellaneous property and investments	586	398
Total other property and investments	10,620	10,386
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,724	1,802
Deferred charges related to income taxes	815	796
Unamortized loss on reacquired debt	263	280
Regulatory assets – asset retirement obligations, deferred	5,418	4,934
Other regulatory assets, deferred	6,902	7,198
Other deferred charges and assets	1,586	1,288
Total deferred charges and other assets	16,708	16,298
Total Assets	127,861	122,935
Current Liabilities:
Securities due within one year	3,286	3,507
Notes payable	707	609
Energy marketing trade payables	0	494
Accounts payable —
Accounts payable	2,229	2,312
Customer deposits	493	487
Accrued taxes —
Accrued income taxes	149	130
Other accrued taxes	797	699
Accrued interest	404	513
Accrued compensation	908	1,025
Asset retirement obligations	690	585
Operating lease obligations	246	241
Other regulatory liabilities	555	509
Other current liabilities	795	968
Total current liabilities	11,259	12,079
Long-term Debt	48,843	45,073
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	8,916	8,175
Deferred credits related to income taxes	5,485	5,767
Accumulated deferred ITCs	2,230	2,235
Employee benefit obligations	1,849	2,213
Operating lease obligations, deferred	1,495	1,611
Asset retirement obligations, deferred	10,919	10,099
Accrued environmental remediation	203	216
Other cost of removal obligations	2,164	2,211
Other regulatory liabilities, deferred	351	251
Other deferred credits and liabilities	637	480
Total deferred credits and other liabilities	34,249	33,258
Total Liabilities	94,351	90,410
Redeemable Preferred Stock of Subsidiaries	291	291
Common Stockholder's Equity (See accompanying statements)	33,219	32,234
Total Liabilities and Stockholders' Equity	127,861	122,935
ALABAMA POWER CO
Current Assets:
Cash and cash equivalents	670	530
Receivables —
Customer accounts	497	429
Unbilled revenues	151	152
Affiliated	53	31
Other accounts and notes	101	66
Accumulated provision for uncollectible accounts	(18)	(43)
Materials and supplies	556	546
Fossil fuel for generation	144	235
Prepaid expenses	65	42
Other regulatory assets	289	226
Other current assets	107	33
Total current assets	2,615	2,247
Property, Plant, and Equipment:
In service	32,787	31,816
Less: Accumulated depreciation	10,298	10,009
Plant in service, net of depreciation	22,489	21,807
Nuclear fuel, at amortized cost	241	270
Construction work in progress	1,129	866
Total property, plant, and equipment	23,859	22,943
Other Property and Investments:
Nuclear decommissioning trusts, at fair value	1,259	1,157
Equity investments in unconsolidated subsidiaries	57	63
Miscellaneous property and investments	129	131
Total other property and investments	1,445	1,351
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	119	151
Deferred charges related to income taxes	238	235
Regulatory assets – asset retirement obligations, deferred	1,580	1,441
Other regulatory assets, deferred	2,100	2,162
Other deferred charges and assets	348	273
Total deferred charges and other assets	4,385	4,262
Total Assets	32,304	30,803
Current Liabilities:
Securities due within one year	616	311
Accounts payable —
Affiliated	299	316
Other	370	545
Customer deposits	106	104
Accrued taxes —
Accrued taxes	331	152
Accrued interest	79	90
Accrued compensation	191	212
Asset retirement obligations	308	254
Other regulatory liabilities	72	108
Other current liabilities	122	107
Total current liabilities	2,494	2,199
Long-term Debt	8,443	8,558
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	3,425	3,273
Deferred credits related to income taxes	1,973	2,016
Accumulated deferred ITCs	89	94
Employee benefit obligations	136	214
Operating lease obligations, deferred	69	119
Asset retirement obligations, deferred	4,015	3,720
Other cost of removal obligations	261	335
Other regulatory liabilities, deferred	139	124
Other deferred credits and liabilities	66	50
Total deferred credits and other liabilities	10,173	9,945
Total Liabilities	21,110	20,702
Redeemable Preferred Stock	291	291
Common Stockholder's Equity (See accompanying statements)	10,903	9,810
Total Liabilities and Stockholders' Equity	32,304	30,803
GEORGIA POWER CO
Current Assets:
Cash and cash equivalents	292	9
Receivables —
Customer accounts	689	621
Unbilled revenues	258	233
Joint owner accounts	106	123
Affiliated	41	21
Other accounts and notes	46	67
Accumulated provision for uncollectible accounts	(2)	(26)
Materials and supplies	647	592
Fossil fuel for generation	201	278
Regulatory assets – storm damage	102	213
Regulatory assets – asset retirement obligations	191	166
Other regulatory assets	243	248
Other current assets	255	143
Total current assets	3,069	2,688
Property, Plant, and Equipment:
In service	40,831	39,682
Less: Accumulated depreciation	12,743	12,251
Plant in service, net of depreciation	28,088	27,431
Nuclear fuel, at amortized cost	564	548
Construction work in progress	7,337	6,857
Total property, plant, and equipment	35,989	34,836
Other Property and Investments:
Nuclear decommissioning trusts, at fair value	1,187	1,145
Equity investments in unconsolidated subsidiaries	50	51
Miscellaneous property and investments	66	63
Total other property and investments	1,303	1,259
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,193	1,308
Deferred charges related to income taxes	544	527
Regulatory assets – asset retirement obligations, deferred	3,607	3,291
Other regulatory assets, deferred	2,515	2,692
Other deferred charges and assets	712	479
Total deferred charges and other assets	8,571	8,297
Total Assets	48,932	47,080
Current Liabilities:
Securities due within one year	672	542
Notes payable	0	60
Accounts payable —
Affiliated	719	597
Other	761	753
Customer deposits	263	276
Accrued taxes —
Accrued taxes	457	407
Accrued interest	98	130
Accrued compensation	207	233
Asset retirement obligations	333	287
Operating lease obligations	153	151
Other regulatory liabilities	360	228
Over recovered fuel clause revenues	0	113
Other current liabilities	198	254
Total current liabilities	4,221	4,031
Long-term Debt	13,064	12,428
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	3,222	3,272
Deferred credits related to income taxes	2,386	2,588
Accumulated deferred ITCs	321	273
Employee benefit obligations	461	586
Operating lease obligations, deferred	1,008	1,156
Asset retirement obligations, deferred	6,432	5,978
Other deferred credits and liabilities	456	267
Total deferred credits and other liabilities	14,286	14,120
Total Liabilities	31,571	30,579
Common Stockholder's Equity (See accompanying statements)	17,361	16,501
Total Liabilities and Stockholders' Equity	48,932	47,080
MISSISSIPPI POWER CO
Current Assets:
Cash and cash equivalents	146	39
Receivables —
Customer accounts	46	34
Unbilled revenues	39	38
Affiliated	45	32
Other accounts and notes	27	32
Materials and supplies	71	65
Fossil fuel for generation	27	24
Assets from risk management activities, net of collateral	66	1
Other regulatory assets	54	60
Other current assets	11	19
Total current assets	532	344
Property, Plant, and Equipment:
In service	5,078	5,011
Less: Accumulated depreciation	1,568	1,545
Plant in service, net of depreciation	3,510	3,466
Construction work in progress	117	146
Total property, plant, and equipment	3,627	3,612
Other Property and Investments:
Total other property and investments	180	151
Deferred Charges and Other Assets:
Deferred charges related to income taxes	31	32
Regulatory assets – asset retirement obligations, deferred	231	201
Other regulatory assets, deferred	371	388
Accumulated deferred income taxes	119	129
Other deferred charges and assets	100	55
Total deferred charges and other assets	852	805
Total Assets	5,191	4,912
Current Liabilities:
Securities due within one year	76	406
Notes payable	0	25
Accounts payable —
Affiliated	88	63
Other	61	109
Accrued taxes —
Accrued taxes	94	114
Accrued interest	7	15
Accrued compensation	31	34
Asset retirement obligations	19	27
Other regulatory liabilities	104	49
Over recovered fuel clause revenues	7	34
Other current liabilities	50	40
Total current liabilities	537	916
Long-term Debt	1,509	1,013
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	464	447
Deferred credits related to income taxes	276	287
Employee benefit obligations	94	113
Asset retirement obligations, deferred	175	150
Other cost of removal obligations	194	194
Other regulatory liabilities, deferred	48	15
Other deferred credits and liabilities	31	35
Total deferred credits and other liabilities	1,282	1,241
Total Liabilities	3,328	3,170
Common Stockholder's Equity (See accompanying statements)	1,863	1,742
Total Liabilities and Stockholders' Equity	5,191	4,912
SOUTHERN POWER CO
Current Assets:
Cash and cash equivalents	192	182
Receivables —
Customer accounts	178	125
Affiliated	68	37
Other accounts and notes	53	27
Materials and supplies	103	157
Prepaid income taxes	15	11
Other current assets	56	36
Total current assets	665	575
Property, Plant, and Equipment:
In service	14,399	13,904
Less: Accumulated depreciation	3,122	2,842
Plant in service, net of depreciation	11,277	11,062
Construction work in progress	274	127
Total property, plant, and equipment	11,551	11,189
Other Property and Investments:
Intangible assets, net of amortization	288	302
Equity investments in unconsolidated subsidiaries	83	19
Net investment in sales-type lease	91	0
Total other property and investments	462	321
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	475	415
Prepaid LTSAs	191	155
Accumulated deferred income taxes	0	262
Income taxes receivable, non-current	33	25
Other deferred charges and assets	234	293
Total deferred charges and other assets	933	1,150
Total Assets	13,611	13,235
Current Liabilities:
Securities due within one year	994	299
Notes payable	27	175
Accounts payable —
Affiliated	110	65
Other	91	92
Accrued taxes —
Accrued income taxes	8	8
Other accrued taxes	27	22
Accrued interest	26	32
Other current liabilities	125	132
Total current liabilities	1,408	825
Long-term Debt	3,021	3,393
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	156	123
Accumulated deferred ITCs	1,629	1,672
Operating lease obligations, deferred	489	426
Other deferred credits and liabilities	201	165
Total deferred credits and other liabilities	2,475	2,386
Total Liabilities	6,904	6,604
Common Stockholder's Equity (See accompanying statements)	6,707	6,631
Total Liabilities and Stockholders' Equity	13,611	13,235
SOUTHERN Co GAS
Current Assets:
Cash and cash equivalents	29	17
Receivables —
Customer accounts	249	353
Energy marketing	0	516
Unbilled revenues	70	219
Affiliated	1	4
Other accounts and notes	39	51
Accumulated provision for uncollectible accounts	(37)	(40)
Natural gas for sale	368	460
Prepaid expenses	181	48
Assets from risk management activities, net of collateral	75	118
Natural gas cost under recovery	432	0
Other regulatory assets	137	102
Other current assets	44	38
Total current assets	1,588	1,886
Property, Plant, and Equipment:
In service	18,527	17,611
Less: Accumulated depreciation	5,004	4,821
Plant in service, net of depreciation	13,523	12,790
Construction work in progress	691	648
Total property, plant, and equipment	14,214	13,438
Other Property and Investments:
Goodwill	5,015	5,015
Equity investments in unconsolidated subsidiaries	1,174	1,290
Other intangible assets, net of amortization	40	51
Miscellaneous property and investments	20	19
Total other property and investments	6,249	6,375
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	72	81
Other regulatory assets, deferred	634	615
Other deferred charges and assets	201	235
Total deferred charges and other assets	907	931
Total Assets	22,958	22,630
Current Liabilities:
Securities due within one year	47	333
Notes payable	662	324
Energy marketing trade payables	0	494
Accounts payable —
Affiliated	42	56
Other	399	373
Customer deposits	106	90
Accrued taxes —
Accrued taxes	79	83
Accrued interest	68	58
Accrued compensation	87	106
Other regulatory liabilities	18	122
Temporary LIFO liquidation	18	0
Other current liabilities	154	150
Total current liabilities	1,680	2,189
Long-term Debt	6,766	6,293
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	1,571	1,265
Deferred credits related to income taxes	822	847
Employee benefit obligations	260	283
Operating lease obligations, deferred	60	67
Accrued environmental remediation	203	216
Other cost of removal obligations	1,675	1,649
Other deferred credits and liabilities	45	54
Total deferred credits and other liabilities	4,636	4,381
Total Liabilities	13,082	12,863
Common Stockholder's Equity (See accompanying statements)	9,876	9,767
Total Liabilities and Stockholders' Equity	$ 22,958	$ 22,630