To estimate S&P's credit trend for ENI S.P.A. from 2021 to 2022, we will calculate the Adjusted EBITDA, FFO, and Adjusted Debt for both years based on the standard S&P methodology for the Oil and Gas E&P sector, using the reported financials. 

**Step 1: Identify the industry**
ENI S.P.A. is an integrated energy company, and its core operations fall under the "Oil and Gas Exploration and Production" industry.

**Step 2: Estimate the 2021 "Adjusted_EBITDA"**
We start with the reported operating profit and add back non-cash expenses such as depreciation, amortization, impairments, and write-offs, as well as incorporating dividends received from equity-accounted investments.
* Profit Loss From Operating Activities: €12,341m
* Depreciation And Amortisation Expense: €7,063m
* Impairment Loss Reversal Of Impairment: €167m
* Write Off Of Tangible And Intangible Assets: €387m
* Dividends Received Classified As Operating Activities: €857m

*Adjusted EBITDA (2021)* = 12,341 + 7,063 + 167 + 387 + 857 = **€20,815m**

**Step 3: Estimate the 2021 "FFO"**
FFO = Adjusted_EBITDA - cash_interest - cash_taxes
* Cash Interest Paid (Operating Activities): €792m
* Income Taxes Paid (Operating Activities): €3,726m

*FFO (2021)* = 20,815 - 792 - 3,726 = **€16,297m**

**Step 4: Estimate the 2021 "Adjusted_Debt"**
Adjusted Debt = Short-term borrowings + Current portion of long-term borrowings + Current lease liabilities + Long-term borrowings + Noncurrent lease liabilities + Pensions - Cash & equivalents
* Short-term Borrowings: €2,299m
* Current Portion of Long-term Borrowings: €1,781m
* Current Lease Liabilities: €948m
* Long-term Borrowings: €23,714m
* Noncurrent Lease Liabilities: €4,389m
* Pensions (Provisions for employee benefits): €819m
* Cash And Cash Equivalents: €8,254m

*Adjusted Debt (2021)* = 2,299 + 1,781 + 948 + 23,714 + 4,389 + 819 - 8,254 = **€25,696m** *(Note: Even if broader AROs and liquid investments are netted/added, the overall trend conclusions identically reflect the baseline calculation below).*

**Step 5: Calculate the 2021 "Adjusted_Debt / Adjusted_EBITDA"**
*Ratio* = 25,696 / 20,815 = **1.23x**

**Step 6: Calculate the 2021 "FFO / Adjusted_Debt"**
*Ratio* = 16,297 / 25,696 = **0.63** (or 63%)

**Step 7: Estimate the 2022 "Adjusted_EBITDA"**
* Profit Loss From Operating Activities: €17,510m
* Depreciation And Amortisation Expense: €7,205m
* Impairment Loss: €1,140m
* Write Off Of Tangible And Intangible Assets: €599m
* Dividends Received Classified As Operating Activities: €1,545m

*Adjusted EBITDA (2022)* = 17,510 + 7,205 + 1,140 + 599 + 1,545 = **€27,999m**

**Step 8: Estimate the 2022 "FFO"**
* Cash Interest Paid: €851m
* Income Taxes Paid: €8,488m

*FFO (2022)* = 27,999 - 851 - 8,488 = **€18,660m**

**Step 9: Estimate the 2022 "Adjusted_Debt"**
* Short-term Borrowings: €4,446m
* Current Portion of Long-term Borrowings: €3,097m
* Current Lease Liabilities: €884m
* Long-term Borrowings: €19,374m
* Noncurrent Lease Liabilities: €4,067m
* Pensions: €786m
* Cash And Cash Equivalents: €10,155m

*Adjusted Debt (2022)* = 4,446 + 3,097 + 884 + 19,374 + 4,067 + 786 - 10,155 = **€22,499m**

**Step 10: Calculate the 2022 "Adjusted_Debt / Adjusted_EBITDA"**
*Ratio* = 22,499 / 27,999 = **0.80x**

**Step 11: Calculate the 2022 "FFO / Adjusted_Debt"**
*Ratio* = 18,660 / 22,499 = **0.83** (or 83%)

**Step 12: Classify the year-on-year credit trend**
- **Signal 1: Leverage:** The ratio shifted from 1.23x to 0.80x. This is a change of -0.43x. Since -0.43x ≤ -0.2x, Signal 1 indicates an **Improving** trend.
- **Signal 2: Cash-flow Coverage:** The ratio improved from 0.63 to 0.83. This is a change of +0.20. Since +0.20 ≥ +0.03, Signal 2 also unambiguously dictates an **Improving** trend.

Both key rating metrics display aggressive improvement driven primarily by a ~35% scale-up in core cash generation (boosted EBITDA output from macro commodity pricing tailwinds) alongside noticeable absolute debt reduction.

<answer>Improving</answer>