| Cover | 12 Months Ended |
| Dec. 31, 2022 | |
| Document Information [Line Items] | |
| Document Type | DEF 14A |
| Amendment Flag | false |
| Entity Information [Line Items] | |
| Entity Registrant Name | ALCOA CORPORATION |
| Entity Central Index Key | 0001675149 |
| Pay vs Performance Disclosure Unit_pure in Millions | 12 Months Ended | ||
| 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 As discussed in the CD&A above, our Compensation Committee has implemented an executive compensation program designed to align pay with performance, retain talent, and drive stockholder value through programs and practices that incorporate sound policies and best practices. The following table sets forth additional compensation information for our NEOs, calculated in accordance with 402(v) of SEC Regulations S-K. year-end, 2022 PAY VERSUS PERFORMANCE Average Non-PEO (d) (1) Average Non-PEO (e) (1)(2) Value of Initial Fixed $100 Adjusted Non-Normalized (4) (in millions) Year (a) Summary (b) (1) Compensation 1 (c) (1)(2) Total (f) (3) Peer Group (g) (3) Net Income (h) (in 2022 $ 12,837,409 $ (1,846,653 ) $ 2,594,429 $ 1,323,816 $ 213.42 $ 178.99 $ 38 $ 2,224 2021 $ 15,960,369 $ 71,419,061 $ 3,334,351 $ 20,670,785 $ 277.59 $ 157.75 $ 570 $ 2,763 2020 $ 13,280,808 $ 14,328,818 $ 3,273,590 $ 4,786,085 $ 107.16 $ 116.44 $ (14 ) $ 1,151 (1) Roy Harvey served as our principal executive officer (“PEO”) for the full year for each of 2022, 2021 and 2020. For 2022, our non-PEO non-PEO non-PEO (2) For each of 2022, 2021 and 2020, the values Included in this column for the compensation actually paid to our PEO and the average compensation actually paid to our non-PEO Roy Harvey (PEO) 2022 2021 2020 Summary Compensation Table Total for PEO (column (b)) $ 12,837,409 $ 15,960,369 $ 13,280,808 - aggregate change in actuarial present value of pension benefits $ 0 $ 0 $ 2,067,235 + service cost of pension benefits $ 0 $ 0 $ 172,579 + prior service cost of pension benefits $ 0 $ 0 $ 0 - SCT “Stock Awards” column value $ 10,474,101 $ 12,113,517 $ 8,468,529 - SCT “Option Awards” column value $ 0 $ 0 $ 0 + year-end year-end $ 4,601,646 $ 31,694,323 $ 12,187,015 +/- year-over-year change in fair value of equity awards granted in prior years that are outstanding and unvested as of the covered year-end $ (8,254,905 ) $ 36,132,923 $ (298,172 ) + vesting date fair value of equity awards granted and vested in the covered year $ 0 $ 0 $ 0 +/- year-over-year change in fair value of equity awards granted in prior years that vested in the covered year $ (556,702 ) $ (255,037 ) $ (477,648 ) - fair value as of prior-year end of equity awards granted in prior years that failed to vest in the covered year $ 0 $ 0 $ 0 + dollar value of dividends/earnings paid prior to the vesting date on equity awards in the covered year $ 0 $ 0 $ 0 + excess fair value for equity award modifications $ 0 $ 0 $ 0 Compensation Actually Paid to PEO (column (c)) $ (1,846,653 ) $ 71,419,061 $ 14,328,818 75 AVERAGE FOR NON-PEO 2022 2021 2020 Average SCT Total for Non-PEO $ 2,594,429 $ 3,334,351 $ 3,273,590 - aggregate change in actuarial present value of pension benefits $ 0 $ 0 $ 744,812 + service cost of pension benefits $ 0 $ 0 $ 122,172 + prior service cost of pension benefits $ 0 $ 0 $ 0 - SCT “Stock Awards” column value $ 1,530,955 $ 1,817,086 $ 1,217,556 - SCT “Option Awards” column value $ 0 $ 0 $ 0 + year-end year-end $ 1,632,281 $ 8,717,424 $ 3,283,942 +/- year-over-year change in fair value of equity awards granted in prior years that are outstanding and unvested as of the covered year-end $ (1,509,632 ) $ 10,469,915 $ 137,089 + vesting date fair value of equity awards granted and vested in the covered year $ 0 $ 0 $ 0 +/- year-over-year change in fair value of equity awards granted in prior years that vested in the covered year $ 137,693 $ (33,819 ) $ (68,340 ) - fair value as of prior-year end of equity awards granted in prior years that failed to vest in the covered year $ 0 $ 0 $ 0 + dollar value of dividends/earnings paid prior to the vesting date on equity awards in the covered year $ 0 $ 0 $ 0 + excess fair value for equity award modifications $ 0 $ 0 $ 0 Average Compensation Actually Paid to Non-PEO $ 1,323,816 $ 20,670,785 $ 4,786,085 (3) Total shareholder return for the Company and the peer group was calculated as the yearly percentage change in cumulative total shareholder return based on a deemed fixed investment of $100 at market close on December 31, 2019 and in accordance with Items 201(e) and 402(v) of Regulation S-K. (4) Adjusted EBITDA, Excluding Special Items—Non-Normalized “Attachment A—Additional Information Regarding Performance Measures | ||
| Company Selected Measure Name | Adjusted EBITDA, Excluding Special Items—Non-Normalized | ||
| Named Executive Officers, Footnote [Text Block] | Roy Harvey served as our principal executive officer (“PEO”) for the full year for each of 2022, 2021 and 2020. For 2022, our non-PEO non-PEO non-PEO | ||
| Peer Group Issuers, Footnote [Text Block] | Total shareholder return for the Company and the peer group was calculated as the yearly percentage change in cumulative total shareholder return based on a deemed fixed investment of $100 at market close on December 31, 2019 and in accordance with Items 201(e) and 402(v) of Regulation S-K. | ||
| PEO Total Compensation Amount | $ 12,837,409 | $ 15,960,369 | $ 13,280,808 |
| PEO Actually Paid Compensation Amount | $ (1,846,653) | 71,419,061 | 14,328,818 |
| Adjustment To PEO Compensation, Footnote [Text Block] | (2) For each of 2022, 2021 and 2020, the values Included in this column for the compensation actually paid to our PEO and the average compensation actually paid to our non-PEO Roy Harvey (PEO) 2022 2021 2020 Summary Compensation Table Total for PEO (column (b)) $ 12,837,409 $ 15,960,369 $ 13,280,808 - aggregate change in actuarial present value of pension benefits $ 0 $ 0 $ 2,067,235 + service cost of pension benefits $ 0 $ 0 $ 172,579 + prior service cost of pension benefits $ 0 $ 0 $ 0 - SCT “Stock Awards” column value $ 10,474,101 $ 12,113,517 $ 8,468,529 - SCT “Option Awards” column value $ 0 $ 0 $ 0 + year-end year-end $ 4,601,646 $ 31,694,323 $ 12,187,015 +/- year-over-year change in fair value of equity awards granted in prior years that are outstanding and unvested as of the covered year-end $ (8,254,905 ) $ 36,132,923 $ (298,172 ) + vesting date fair value of equity awards granted and vested in the covered year $ 0 $ 0 $ 0 +/- year-over-year change in fair value of equity awards granted in prior years that vested in the covered year $ (556,702 ) $ (255,037 ) $ (477,648 ) - fair value as of prior-year end of equity awards granted in prior years that failed to vest in the covered year $ 0 $ 0 $ 0 + dollar value of dividends/earnings paid prior to the vesting date on equity awards in the covered year $ 0 $ 0 $ 0 + excess fair value for equity award modifications $ 0 $ 0 $ 0 Compensation Actually Paid to PEO (column (c)) $ (1,846,653 ) $ 71,419,061 $ 14,328,818 | ||
| Non-PEO NEO Average Total Compensation Amount | $ 2,594,429 | 3,334,351 | 3,273,590 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 1,323,816 | 20,670,785 | 4,786,085 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | AVERAGE FOR NON-PEO 2022 2021 2020 Average SCT Total for Non-PEO $ 2,594,429 $ 3,334,351 $ 3,273,590 - aggregate change in actuarial present value of pension benefits $ 0 $ 0 $ 744,812 + service cost of pension benefits $ 0 $ 0 $ 122,172 + prior service cost of pension benefits $ 0 $ 0 $ 0 - SCT “Stock Awards” column value $ 1,530,955 $ 1,817,086 $ 1,217,556 - SCT “Option Awards” column value $ 0 $ 0 $ 0 + year-end year-end $ 1,632,281 $ 8,717,424 $ 3,283,942 +/- year-over-year change in fair value of equity awards granted in prior years that are outstanding and unvested as of the covered year-end $ (1,509,632 ) $ 10,469,915 $ 137,089 + vesting date fair value of equity awards granted and vested in the covered year $ 0 $ 0 $ 0 +/- year-over-year change in fair value of equity awards granted in prior years that vested in the covered year $ 137,693 $ (33,819 ) $ (68,340 ) - fair value as of prior-year end of equity awards granted in prior years that failed to vest in the covered year $ 0 $ 0 $ 0 + dollar value of dividends/earnings paid prior to the vesting date on equity awards in the covered year $ 0 $ 0 $ 0 + excess fair value for equity award modifications $ 0 $ 0 $ 0 Average Compensation Actually Paid to Non-PEO $ 1,323,816 $ 20,670,785 $ 4,786,085 | ||
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | |||
| Compensation Actually Paid vs. Net Income [Text Block] | |||
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | |||
| Total Shareholder Return Vs Peer Group [Text Block] | |||
| Tabular List [Table Text Block] | Tabular List The following table lists the financial performance measures that we believe represent the most important financial performance measures we use to link compensation actually paid to our NEOs for fiscal 2022 to our performance: Relative Total Shareholder Return Average Return on Equity Adj. EBITDA excluding special items (non-normalized) Free Cash Flow (normalized) | ||
| Total Shareholder Return Amount | $ 213.42 | 277.59 | 107.16 |
| Peer Group Total Shareholder Return Amount | 178.99 | 157.75 | 116.44 |
| Net Income (Loss) | $ 38,000,000 | $ 570,000,000 | $ (14,000,000) |
| Company Selected Measure Amount | 2,224 | 2,763 | 1,151 |
| PEO Name | Roy Harvey | ||
| Measure [Axis]: 1 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Relative Total Shareholder Return | ||
| Measure [Axis]: 2 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Average Return on Equity | ||
| Measure [Axis]: 3 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Adj. EBITDA excluding special items (non-normalized) | ||
| Non-GAAP Measure Description [Text Block] | Adjusted EBITDA, Excluding Special Items—Non-Normalized “Attachment A—Additional Information Regarding Performance Measures | ||
| Measure [Axis]: 4 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Free Cash Flow (normalized) | ||
| PEO [Member] | Change In Pension Value and Equity Award Value [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ 0 | $ 0 | $ 2,067,235 |
| PEO [Member] | Pension Adjustments Prior Service Cost [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Pension Adjustments Service Cost [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 172,579 |
| PEO [Member] | Change In Fair Value Of Outstanding And Unvested Awards Granted In Prior Fiscal Years [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (8,254,905) | 36,132,923 | (298,172) |
| PEO [Member] | Adjustments For Equity Awards Failed To Meet Performance Conditions [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Dividends Or Other Earnings Paid On Equity Awards Not Otherwise Reflected In Fair Value [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | SCT Stock Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 10,474,101 | 12,113,517 | 8,468,529 |
| PEO [Member] | SCT Option Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Year End Fair Value Of Equity Awards Granted In The Covered Year That Are Outstanding And Unvested As Of The Covered Year End [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 4,601,646 | 31,694,323 | 12,187,015 |
| PEO [Member] | Year Over Year Change In Fair Value Of Equity Awards Granted In Prior Years That Vested In The Covered Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (556,702) | (255,037) | (477,648) |
| PEO [Member] | Excess Fair Value For Equity Award Modifications [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Change In Fair Value As Of Vesting Date Of Awards Granted And Vested During Current Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| Non-PEO NEO [Member] | Change In Pension Value and Equity Award Value [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 744,812 |
| Non-PEO NEO [Member] | Pension Adjustments Prior Service Cost [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| Non-PEO NEO [Member] | Pension Adjustments Service Cost [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 122,172 |
| Non-PEO NEO [Member] | Change In Fair Value Of Outstanding And Unvested Awards Granted In Prior Fiscal Years [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (1,509,632) | 10,469,915 | 137,089 |
| Non-PEO NEO [Member] | Adjustments For Equity Awards Failed To Meet Performance Conditions [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| Non-PEO NEO [Member] | Dividends Or Other Earnings Paid On Equity Awards Not Otherwise Reflected In Fair Value [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| Non-PEO NEO [Member] | SCT Stock Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 1,530,955 | 1,817,086 | 1,217,556 |
| Non-PEO NEO [Member] | SCT Option Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| Non-PEO NEO [Member] | Year End Fair Value Of Equity Awards Granted In The Covered Year That Are Outstanding And Unvested As Of The Covered Year End [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 1,632,281 | 8,717,424 | 3,283,942 |
| Non-PEO NEO [Member] | Year Over Year Change In Fair Value Of Equity Awards Granted In Prior Years That Vested In The Covered Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 137,693 | (33,819) | (68,340) |
| Non-PEO NEO [Member] | Excess Fair Value For Equity Award Modifications [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| Non-PEO NEO [Member] | Change In Fair Value As Of Vesting Date Of Awards Granted And Vested During Current Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ 0 | $ 0 | $ 0 |
