Condensed Consolidated Statements of Cash Flows (Unaudited) - GAS - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Operating Activities:
Net income	$ 2,214	$ 2,332
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	2,860	2,572
Deferred income taxes	453	247
Other, net	76	(116)
Changes in certain current assets and liabilities —
Receivables	(130)	(284)
Natural gas for sale, net of temporary LIFO liquidation	233	188
Other current assets	61	(86)
Accounts payable	(695)	(247)
Other current liabilities	26	204
Net cash provided from operating activities	3,431	3,999
Investing Activities:
Property additions	(5,237)	(3,895)
Cost of removal, net of salvage	(304)	(282)
Change in construction payables, net	(42)	(217)
Other investing activities	(153)	(172)
Net cash used for investing activities	(5,734)	(4,222)
Financing Activities:
Increase (decrease) in notes payable, net	(150)	(1,125)
Payment of common stock dividends	(1,494)	(1,487)
Other financing activities	(150)	(135)
Net cash provided from financing activities	2,467	513
Net Change in Cash, Cash Equivalents, and Restricted Cash	164	290
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	1,101	921
Cash, Cash Equivalents, and Restricted Cash at End of Period	1,265	1,211
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	1,287	1,235
Income taxes, net (excludes credit transfers)	199	62
Noncash transactions —
Accrued property additions at end of period	1,091	805
Right-of-use assets obtained under operating leases	114	98
SOUTHERN Co GAS
Operating Activities:
Net income	524	517
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	338	310
Deferred income taxes	67	211
Other, net	26	50
Changes in certain current assets and liabilities —
Receivables	209	310
Natural gas for sale, net of temporary LIFO liquidation	233	188
Other current assets	37	(48)
Accounts payable	(105)	(112)
Natural gas cost over recovery	(87)	(43)
Other current liabilities	(32)	(113)
Net cash provided from operating activities	1,210	1,270
Investing Activities:
Property additions	(677)	(657)
Cost of removal, net of salvage	(42)	(38)
Change in construction payables, net	15	20
Other investing activities	(31)	(21)
Net cash used for investing activities	(735)	(696)
Financing Activities:
Increase in notes payable, net	16
Increase (decrease) in notes payable, net		(274)
Proceeds — Other long-term debt	0	9
Return of capital to parent company	(23)	0
Capital contributions from parent company	22	3
Payment of common stock dividends	(297)	(302)
Other financing activities	(12)	(10)
Net cash provided from financing activities	(294)	(574)
Net Change in Cash, Cash Equivalents, and Restricted Cash	181	0
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	44	35
Cash, Cash Equivalents, and Restricted Cash at End of Period	225	35
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	185	164
Income taxes, net (excludes credit transfers)	66	(52)
Noncash transactions —
Accrued property additions at end of period	101	159
Right-of-use assets obtained under operating leases	60	1
Return of capital to parent company	$ 33	$ 0