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Derivatives - Schedule of Pre-Tax Effects of Cash Flow and Fair Value Hedging on Income (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2023 | Jun. 30, 2022 | Jun. 30, 2023 | Jun. 30, 2022
Derivative [Line Items] |  |  |  |
Depreciation and amortization | $ 1,112 | $ 913 | $ 2,222 | $ 1,805
Total interest expense, net of amounts capitalized | (610) | (488) | (1,192) | (950)
Total other income (expense), net | 142 | 139 | 286 | 283
Natural gas |  |  |  |
Derivative [Line Items] |  |  |  |
Total cost of sales | 199 | 452 | 1,097 | 1,546
Other Income (Expense) |  |  |  |
Derivative [Line Items] |  |  |  |
Amount excluded from effectiveness testing recognized in earnings | (29) | 7 | (1) | 3
Cash Flow Hedging | Energy-related derivatives | Cost of Sales |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | (9) | 10 | (29) | 18
Cash Flow Hedging | Energy-related derivatives | Depreciation and Amortization |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | (4) | 4 | (13) | 6
Cash Flow Hedging | Interest rate derivatives | Interest Expense |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | (5) | (6) | (9) | (13)
Cash Flow Hedging | Foreign currency derivatives | Interest Expense |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | (2) | (7) | (5) | (13)
Cash Flow Hedging | Foreign currency derivatives | Other Income (Expense) |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | 0 | (73) | 10 | (97)
Fair Value Hedging | Interest rate derivatives | Interest Expense |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | (45) | (76) | (3) | (198)
Fair Value Hedging | Foreign currency derivatives | Other Income (Expense) |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | 29 | (96) | 26 | (121)
SOUTHERN POWER CO |  |  |  |
Derivative [Line Items] |  |  |  |
Depreciation and amortization | 122 | 131 | 250 | 251
Total interest expense, net of amounts capitalized | (33) | (36) | (66) | (73)
Total other income (expense), net | 2 | 1 | 4 | 3
SOUTHERN POWER CO | Cash Flow Hedging | Energy-related derivatives | Depreciation and Amortization |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | (4) | 4 | (13) | 6
SOUTHERN POWER CO | Cash Flow Hedging | Foreign currency derivatives | Interest Expense |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | (2) | (7) | (5) | (13)
SOUTHERN POWER CO | Cash Flow Hedging | Foreign currency derivatives | Other Income (Expense) |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | 0 | (73) | 10 | (97)
SOUTHERN Co GAS |  |  |  |
Derivative [Line Items] |  |  |  |
Depreciation and amortization | 143 | 138 | 284 | 275
Total interest expense, net of amounts capitalized | (73) | (61) | (150) | (122)
Total other income (expense), net | 17 | 16 | 32 | 32
SOUTHERN Co GAS | Natural gas |  |  |  |
Derivative [Line Items] |  |  |  |
Total cost of sales | 199 | 452 | 1,097 | 1,546
SOUTHERN Co GAS | Cash Flow Hedging | Energy-related derivatives | Cost of Sales |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | (9) | 10 | (29) | 18
SOUTHERN Co GAS | Cash Flow Hedging | Interest rate derivatives | Interest Expense |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | 0 | (1) | (1) | (1)
SOUTHERN Co GAS | Fair Value Hedging | Interest rate derivatives | Interest Expense |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | (15) | (22) | (2) | (57)
Traditional Electric Operating Companies | Cash Flow Hedging | Interest rate derivatives | Interest Expense |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | 0 | 0 | 0 | 0
Traditional Electric Operating Companies | Fair Value Hedging | Interest rate derivatives | Interest Expense |  |  |  |
Derivative [Line Items] |  |  |  |
Gain (loss) on hedges | $ 0 | $ 0 | $ 0 | $ 0

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- Definition The current period expense charged against earnings on long-lived, physical assets used in the normal conduct of business and not intended for resale to allocate or recognize the cost of assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset. Excludes amortization of nuclear fuel. + References No definition available. + Details
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