| Cover | 12 Months Ended |
| Dec. 31, 2023 | |
| Cover [Abstract] | |
| Document Type | PRE 14A |
| Entity Registrant Name | The Southern Company |
| Entity Central Index Key | 0000092122 |
| Amendment Flag | false |
| Pay vs Performance Disclosure | 5 Months Ended | 7 Months Ended | 12 Months Ended | |||
| May 24, 2023 | Dec. 31, 2023 | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | |
| Pay vs Performance Disclosure [Table] | ||||||
| Pay vs Performance [Table Text Block] | Pay Versus Performance Disclosure This disclosure has been prepared in accordance with the SEC’s pay versus performance rules in Item 402(v) of Regulation S-K under the 1934 Act (Item 402(v)) and does not necessarily reflect value actually realized by the NEOs or how the Compensation Committee evaluates compensation decisions in light of Company or individual performance. For a discussion of how the Compensation Committee seeks to align pay with performance when making compensation decisions, see the Compensation Discussion and Analysis beginning on page 45 . The following tables and related disclosures provide information about (i) the total compensation of our principal executive officers (CEOs or PEOs) and our non-CEO NEOs (collectively, the Other NEOs) as presented in the Summary Compensation Table on page 75 , (ii) the compensation actually paid (CAP) to our CEOs and our Other NEOs, as calculated pursuant to Item 402(v), (iii) certain financial performance measures, and (iv) the relationship of CAP to those financial performance measures. PEO Pay Non-PEO Pay Value of Initial Fixed Percentile Fiscal Year (a) Summary Compensation Table Total for CEO ($) (b) Compensation Actually Paid to CEO ($) (c) Average Summary Compensation Table Total for non-CEO NEOs ($) (d) Average Compensation Actually Paid to non-CEO NEOs ($) (e) Southern Total Shareholder Return ($) (f) Peer Group Total Shareholder Return ($) (g) Net Income ($s millions) (h) Selected Measure One-Year Relative TSR Percentile ($) (i) Womack Fanning Womack Fanning 2023 23,521,052 33,469,800 18,378,941 40,567,478 5,555,346 6,433,480 129.49 101.02 3,976 86th 2022 — 24,006,670 — 42,131,615 5,668,554 6,722,302 126.71 111.24 3,524 77th 2021 — 21,243,559 — 35,516,807 5,210,958 7,015,374 117.07 113.92 2,393 45th 2020 — 22,366,850 — 23,821,625 7,160,434 6,386,601 100.63 99.38 3,119 70th | |||||
| Named Executive Officers, Footnote [Text Block] | Names of CEOs and Other NEOs (columns (b), (c), (d) and (e)) 2023: CEO - Thomas A. Fanning Christopher C. Womack 2022: CEO - Thomas A. Fanning 2021: CEO - Thomas A. Fanning 2020: CEO - Thomas A. Fanning | |||||
| Peer Group Issuers, Footnote [Text Block] | Column (g) The peer group utilized in the table above is the Philadelphia Utilities Sector Index (UTY). For each Covered Year, the peer group cumulative TSR was calculated based on a deemed fixed investment of $100 in the index through each Measurement Period, assuming dividend reinvestment. | |||||
| Adjustment To PEO Compensation, Footnote [Text Block] | Column (c and e) To calculate Compensation Actually Paid (CAP) to the CEO for 2023, the following amounts were deducted from and added to the “Total” compensation amount for the CEO reflected in each year’s Summary Compensation Table (SCT): 2023 Fiscal Year Summary Minus: SCT Minus: SCT “Change in Nonqualified Deferred Add: Stock Add: Pension Compensation Womack 23,521,052 10,009,683 9,352,563 13,885,386 334,749 18,378,941 Fanning 33,469,800 17,375,310 10,050,149 33,398,578 1,106,559 40,567,478 Average 5,555,346 2,349,586 1,052,475 3,956,833 323,362 6,433,480 The deductions of “Stock Awards” and “Change in Pension Value and Nonqualified Deferred Compensation” are found in columns (d) and (f) of the SCT for each covered year. Stock Award Fair Value The addition of Stock Award Fair Value reflects: PEO Average Womack Fanning Non-PEO NEOs Fair Value of Awards Granted during Year that remain unvested as of Year-End $ 12,937,890 $ 27,765,593 $ 3,271,123 Fair Value of Awards Granted during Year that vested during such Year — — — Change in Fair Value from prior December 31 to December 31 of Year of Awards Granted in Prior Years that remain outstanding and unvested $ 617,855 $ 4,531,859 $ 468,646 Change in Fair Value from Prior December 31 to Vesting Date for Awards that vested during Year $ 329,641 $ 1,101,126 $ 217,064 Deduction of Fair Value of Awards Granted in Prior Years that were forfeited during Year — — — Increase based upon Incremental Fair Value of Awards modified during Year — — — Increase based on Dividends or Other Earnings Paid during Year prior to Vesting Date of Award — — — Total $ 13,885,386 $ 33,398,578 $ 3,956,833 Stock Award Fair Value was calculated based on the probable outcome of performance conditions as of the relevant measurement date, consistent with the approach described on page 75 . Pension Service Cost The addition of Pension Service Costs reflects the annual service costs for the Pension Plan and supplemental pension plans described on page 81 . ► Womack: Pension Plan - $45,318; SBP-P and SERP - $289,431 ► Fanning: Pension Plan - $43,523; SBP-P and SERP - $1,063,036 ► Average Non-PEO NEOs: Pension Plan - $41,908; SBP-P and SERP - $281,455 There were no plan amendments during the covered year that resulted in prior service costs. Column (f) For each Covered Year, our absolute TSR was calculated based on the yearly percentage change in our cumulative TSR on our common stock, par value $5.00 per share, measured as the quotient of (a) the sum of (i) the cumulative amount of dividends for the period beginning with our closing stock price on the NYSE on December 31, 2019 through and including the last day of the covered year (each, a Measurement Period), assuming dividend reinvestment, plus (ii) the difference between our closing stock price at the end versus the beginning of the Measurement Period, divided by (b) our closing share price at the beginning of the Measurement Period. Each of these yearly percentage changes was then applied to a deemed fixed investment of $100 at the beginning of each Measurement Period to produce the Covered Year-end values of such investment as of the end of 2023, 2022, 2021 and 2020, as applicable. Because Covered Years are presented in the table in reverse chronological order (from top to bottom), the table should be read from bottom to top for purposes of understanding cumulative returns over time. | |||||
| Non-PEO NEO Average Total Compensation Amount | $ 5,555,346 | $ 5,668,554 | $ 5,210,958 | $ 7,160,434 | ||
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 6,433,480 | 6,722,302 | 7,015,374 | 6,386,601 | ||
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | Column (c and e) To calculate Compensation Actually Paid (CAP) to the CEO for 2023, the following amounts were deducted from and added to the “Total” compensation amount for the CEO reflected in each year’s Summary Compensation Table (SCT): 2023 Fiscal Year Summary Minus: SCT Minus: SCT “Change in Nonqualified Deferred Add: Stock Add: Pension Compensation Womack 23,521,052 10,009,683 9,352,563 13,885,386 334,749 18,378,941 Fanning 33,469,800 17,375,310 10,050,149 33,398,578 1,106,559 40,567,478 Average 5,555,346 2,349,586 1,052,475 3,956,833 323,362 6,433,480 The deductions of “Stock Awards” and “Change in Pension Value and Nonqualified Deferred Compensation” are found in columns (d) and (f) of the SCT for each covered year. Stock Award Fair Value The addition of Stock Award Fair Value reflects: PEO Average Womack Fanning Non-PEO NEOs Fair Value of Awards Granted during Year that remain unvested as of Year-End $ 12,937,890 $ 27,765,593 $ 3,271,123 Fair Value of Awards Granted during Year that vested during such Year — — — Change in Fair Value from prior December 31 to December 31 of Year of Awards Granted in Prior Years that remain outstanding and unvested $ 617,855 $ 4,531,859 $ 468,646 Change in Fair Value from Prior December 31 to Vesting Date for Awards that vested during Year $ 329,641 $ 1,101,126 $ 217,064 Deduction of Fair Value of Awards Granted in Prior Years that were forfeited during Year — — — Increase based upon Incremental Fair Value of Awards modified during Year — — — Increase based on Dividends or Other Earnings Paid during Year prior to Vesting Date of Award — — — Total $ 13,885,386 $ 33,398,578 $ 3,956,833 Stock Award Fair Value was calculated based on the probable outcome of performance conditions as of the relevant measurement date, consistent with the approach described on page 75 . Pension Service Cost The addition of Pension Service Costs reflects the annual service costs for the Pension Plan and supplemental pension plans described on page 81 . ► Womack: Pension Plan - $45,318; SBP-P and SERP - $289,431 ► Fanning: Pension Plan - $43,523; SBP-P and SERP - $1,063,036 ► Average Non-PEO NEOs: Pension Plan - $41,908; SBP-P and SERP - $281,455 There were no plan amendments during the covered year that resulted in prior service costs. Column (f) For each Covered Year, our absolute TSR was calculated based on the yearly percentage change in our cumulative TSR on our common stock, par value $5.00 per share, measured as the quotient of (a) the sum of (i) the cumulative amount of dividends for the period beginning with our closing stock price on the NYSE on December 31, 2019 through and including the last day of the covered year (each, a Measurement Period), assuming dividend reinvestment, plus (ii) the difference between our closing stock price at the end versus the beginning of the Measurement Period, divided by (b) our closing share price at the beginning of the Measurement Period. Each of these yearly percentage changes was then applied to a deemed fixed investment of $100 at the beginning of each Measurement Period to produce the Covered Year-end values of such investment as of the end of 2023, 2022, 2021 and 2020, as applicable. Because Covered Years are presented in the table in reverse chronological order (from top to bottom), the table should be read from bottom to top for purposes of understanding cumulative returns over time. | |||||
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | Compensation Actually Paid v. Southern TSR & Peer Group TSR | |||||
| Compensation Actually Paid vs. Net Income [Text Block] | Compensation Actually Paid vs. Net Income | |||||
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | Compensation Actually Paid vs. 1-Yr rTSR* | |||||
| Tabular List [Table Text Block] | Most Important Performance Measures This table provides what the Company believes represent the most important financial performance measures (including relative TSR) we used to link CAP for our PEO and non-PEO NEOs for 2023 to our performance for 2023: 1-year Relative TSR 3-year Relative TSR Return on Equity (ROE) Earnings per Share (EPS) GHG Reduction Metric | |||||
| Total Shareholder Return Amount | $ 129.49 | 126.71 | 117.07 | 100.63 | ||
| Peer Group Total Shareholder Return Amount | 101.02 | 111.24 | 113.92 | 99.38 | ||
| Net Income (Loss) Attributable to Parent | $ 3,976,000,000 | $ 3,524,000,000 | $ 2,393,000,000 | $ 3,119,000,000 | ||
| Company Selected Measure Amount | 86 | 77 | 45 | 70 | ||
| PEO Name | Thomas A. Fanning | Christopher C. Womack | Thomas A. Fanning | Thomas A. Fanning | Thomas A. Fanning | |
| Measure [Axis]: 1 | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Measure Name | 1-year Relative TSR | |||||
| Measure [Axis]: 2 | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Measure Name | 3-year Relative TSR | |||||
| Measure [Axis]: 3 | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Measure Name | Return on Equity (ROE) | |||||
| Measure [Axis]: 4 | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Measure Name | Earnings per Share (EPS) | |||||
| Measure [Axis]: 5 | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Measure Name | GHG Reduction Metric | |||||
| Non P E O Stock Awards [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | $ 2,349,586 | |||||
| Non P E O Change In Pension Value And Nonqualified Deferred Compensation [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 1,052,475 | |||||
| Non P E O Stock Award Fair Value [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 3,956,833 | |||||
| Non P E O Pension Service Costs [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 323,362 | |||||
| Non P E O Fair Value Of Awards Granted During Year That Remain Unvested As Of Year End [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 3,271,123 | |||||
| Non P E O Fair Value Of Awards Granted During Year That Vested During Such Year [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 0 | |||||
| Non P E O Change In Fair Value From Prior December 31 To December 31 Of Year Of Awards Granted In Prior Years That Remain Outstanding And Unvested [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 468,646 | |||||
| Non P E O Change In Fair Value From Prior December 31 To Vesting Date For Awards That Vested During Year [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 217,064 | |||||
| Non P E O Deduction Of Fair Value Of Awards Grantedin Prior Years That Were Forfeited During Year [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 0 | |||||
| Non P E O Increase Based Upon Incremental Fair Value Of Awards Modified During Year [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 0 | |||||
| Non P E O Increase Based On Dividends Or Other Earnings Paid During Year Prior To Vesting Date Of Award [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 0 | |||||
| Non P E O Total [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 3,956,833 | |||||
| Womack [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| PEO Total Compensation Amount | 23,521,052 | $ 0 | $ 0 | $ 0 | ||
| PEO Actually Paid Compensation Amount | 18,378,941 | 0 | 0 | 0 | ||
| Womack [Member] | Stock Awards [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 10,009,683 | |||||
| Womack [Member] | Change In Pension Value And Nonqualified Deferred Compensation [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 9,352,563 | |||||
| Womack [Member] | Stock Award Fair Value [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 13,885,386 | |||||
| Womack [Member] | Pension Service Costs [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 334,749 | |||||
| Womack [Member] | Fair Value Of Awards Granted During Year That Remain Unvested As Of Year End [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 12,937,890 | |||||
| Womack [Member] | Fair Value Of Awards Granted During Year That Vested During Such Year [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 0 | |||||
| Womack [Member] | Change In Fair Value From Prior December 31 To December 31 Of Year Of Awards Granted In Prior Years That Remain Outstanding And Unvested [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 617,855 | |||||
| Womack [Member] | Change In Fair Value From Prior December 31 To Vesting Date For Awards That Vested During Year [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 329,641 | |||||
| Womack [Member] | Deduction Of Fair Value Of Awards Grantedin Prior Years That Were Forfeited During Year [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 0 | |||||
| Womack [Member] | Increase Based Upon Incremental Fair Value Of Awards Modified During Year [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 0 | |||||
| Womack [Member] | Increase Based On Dividends Or Other Earnings Paid During Year Prior To Vesting Date Of Award [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 0 | |||||
| Womack [Member] | Total [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 13,885,386 | |||||
| Fanning [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| PEO Total Compensation Amount | 33,469,800 | 24,006,670 | 21,243,559 | 22,366,850 | ||
| PEO Actually Paid Compensation Amount | 40,567,478 | $ 42,131,615 | $ 35,516,807 | $ 23,821,625 | ||
| Fanning [Member] | Stock Awards [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 17,375,310 | |||||
| Fanning [Member] | Change In Pension Value And Nonqualified Deferred Compensation [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 10,050,149 | |||||
| Fanning [Member] | Stock Award Fair Value [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 33,398,578 | |||||
| Fanning [Member] | Pension Service Costs [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 1,106,559 | |||||
| Fanning [Member] | Fair Value Of Awards Granted During Year That Remain Unvested As Of Year End [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 27,765,593 | |||||
| Fanning [Member] | Fair Value Of Awards Granted During Year That Vested During Such Year [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 0 | |||||
| Fanning [Member] | Change In Fair Value From Prior December 31 To December 31 Of Year Of Awards Granted In Prior Years That Remain Outstanding And Unvested [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 4,531,859 | |||||
| Fanning [Member] | Change In Fair Value From Prior December 31 To Vesting Date For Awards That Vested During Year [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 1,101,126 | |||||
| Fanning [Member] | Deduction Of Fair Value Of Awards Grantedin Prior Years That Were Forfeited During Year [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 0 | |||||
| Fanning [Member] | Increase Based Upon Incremental Fair Value Of Awards Modified During Year [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 0 | |||||
| Fanning [Member] | Increase Based On Dividends Or Other Earnings Paid During Year Prior To Vesting Date Of Award [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | 0 | |||||
| Fanning [Member] | Total [Member] | ||||||
| Pay vs Performance Disclosure [Table] | ||||||
| Adjustment to Compensation Amount | $ 33,398,578 | |||||
