### Step 1: Identify the relevant industry
ENEL - SPA is a major multinational energy company, primarily engaged in the generation, transmission, distribution, and sale of electricity and gas. It operates across multiple geographies and segments (including regulated networks, renewable generation, and retail). The provided S&P methodologies for **Regulated Utilities** and **Unregulated Power And Gas** are the most applicable. We will follow the principles for utilities.

### Step 2: Estimate 2021 Adjusted_EBITDA
Formula: Adjusted_EBITDA = EBITDA + adjustment_leases + nonrecurring_losses - nonrecurring_gains ± other_normalization_adjustments

For 2021:
- Profit Loss From Operating Activities (EBIT) = 7,551,000,000 EUR
- Depreciation Amortisation And Impairment Loss = 8,507,000,000 EUR
- Other Work Performed By Entity And Capitalised = 3,041,000,000 EUR
- EBITDA (Reported) = EBIT + Depreciation + Capitalized Work = 7,551,000,000 + 8,507,000,000 + 3,041,000,000 = 19,099,000,000 EUR
- Adjustment for leases (approx 8x rent expense): Employee benefits (5,140,000,000) and Services & other materials (19,240,000,000) typically contain rent. Assuming ~0.5% - 1% as rent expense for a utility, estimated rent ~ 150,000,000 EUR. 8x rent = ~1,200,000,000 EUR.
- Other normalization adjustments: None explicitly identified from the data. 
- Adjusted_EBITDA (2021) = 19,099,000,000 + 1,200,000,000 = **20,299,000,000 EUR**

### Step 3: Estimate 2021 FFO
Formula: FFO = Adjusted_EBITDA - cash_interest - cash_taxes

For 2021:
- Cash Interest: Finance Costs Paid Classified As Operating Activities = 4,277,000,000 EUR
- Cash Taxes: Income Taxes Paid Refund Classified As Operating Activities = 1,846,000,000 EUR
- FFO (2021) = 20,299,000,000 - 4,277,000,000 - 1,846,000,000 = **14,176,000,000 EUR**

### Step 4: Estimate 2021 Adjusted_Debt
Formula: Adjusted_Debt = (reported_debt + leases + pension_deficit + guarantees + hybrid_debt_portion + other_debt_like_items) - eligible_cash

For 2021 (balances as of 2022-01-01):
- Reported Debt = Longterm Borrowings (54,500,000,000) + Current Portion of LT Borrowings (4,031,000,000) + Shortterm Borrowings (13,306,000,000) = 71,837,000,000 EUR
- Leases (debt-like): 8x rent = 1,200,000,000 EUR
- Pension deficit: Noncurrent Provisions for Employee Benefits (2,724,000,000) + Other Shortterm Provisions (1,126,000,000) = 3,850,000,000 EUR (using provisions as proxy for deficit)
- Hybrid debt: Equity Instruments Perpetual Hybrid Bonds Member (5,567,000,000) ~ 50% equity credit = 2,783,500,000 EUR debt portion
- Other debt-like items: Noncurrent Contract Liabilities (6,214,000,000) + Current Contract Liabilities (1,433,000,000) = 7,647,000,000 EUR
- Eligible Cash: Cash And Cash Equivalents (8,858,000,000). *Note: Per S&P methodology for utilities with seasonal working capital, we net inventory (3,109,000,000) against short-term borrowings (13,306,000,000). Net ST Debt = 10,197,000,000.*
- Adjusted_Debt (2021) = (10,197,000,000 + 54,500,000,000) + 1,200,000,000 + 3,850,000,000 + 2,783,500,000 + 7,647,000,000 - 8,858,000,000 = **71,319,500,000 EUR**

### Step 5: Calculate 2021 Adjusted_Debt / Adjusted_EBITDA
Ratio (2021) = 71,319,500,000 / 20,299,000,000 = **3.51x**

### Step 6: Calculate 2021 FFO / Adjusted_Debt
Ratio (2021) = 14,176,000,000 / 71,319,500,000 = **19.88%** (0.1988)

### Step 7: Estimate 2022 Adjusted_EBITDA
For 2022:
- Profit Loss From Operating Activities (EBIT) = 11,193,000,000 EUR
- Depreciation Amortisation And Impairment Loss = 7,447,000,000 EUR
- Other Work Performed By Entity And Capitalised = 3,415,000,000 EUR
- EBITDA (Reported) = 11,193,000,000 + 7,447,000,000 + 3,415,000,000 = 22,055,000,000 EUR
- Adjustment for leases: Employee benefits (4,570,000,000) + Services & other materials (20,228,000,000). Estimated rent ~ 150,000,000. 8x rent = 1,200,000,000 EUR.
- Adjusted_EBITDA (2022) = 22,055,000,000 + 1,200,000,000 = **23,255,000,000 EUR**

### Step 8: Estimate 2022 FFO
For 2022:
- Cash Interest: Finance Costs Paid Classified As Operating Activities = 5,016,000,000 EUR
- Cash Taxes: Income Taxes Paid Refund Classified As Operating Activities = 1,934,000,000 EUR
- FFO (2022) = 23,255,000,000 - 5,016,000,000 - 1,934,000,000 = **16,305,000,000 EUR**

### Step 9: Estimate 2022 Adjusted_Debt
For 2022 (balances as of 2023-01-01):
- Reported Debt = Longterm Borrowings (68,191,000,000) + Current Portion of LT Borrowings (2,835,000,000) + Shortterm Borrowings (18,392,000,000) = 89,418,000,000 EUR
- Leases (debt-like): 1,200,000,000 EUR
- Pension deficit: Noncurrent Provisions for Employee Benefits (2,202,000,000) + Other Shortterm Provisions (1,325,000,000) = 3,527,000,000 EUR
- Hybrid debt: Equity Instruments Perpetual Hybrid Bonds Member (5,567,000,000) ~ 50% equity credit = 2,783,500,000 EUR debt portion
- Other debt-like items: Noncurrent Contract Liabilities (5,747,000,000) + Current Contract Liabilities (1,775,000,000) = 7,522,000,000 EUR
- Eligible Cash: Cash And Cash Equivalents (11,041,000,000). Net ST Debt against Inventory (4,853,000,000). Net ST Debt = 18,392,000,000 - 4,853,000,000 = 13,539,000,000.
- Adjusted_Debt (2022) = (13,539,000,000 + 68,191,000,000) + 1,200,000,000 + 3,527,000,000 + 2,783,500,000 + 7,522,000,000 - 11,041,000,000 = **85,721,500,000 EUR**

### Step 10: Calculate 2022 Adjusted_Debt / Adjusted_EBITDA
Ratio (2022) = 85,721,500,000 / 23,255,000,000 = **3.69x**

### Step 11: Calculate 2022 FFO / Adjusted_Debt
Ratio (2022) = 16,305,000,000 / 85,721,500,000 = **19.02%** (0.1902)

### Step 12: Classify the year-on-year credit trend
- Signal 1 (Leverage): Change in Adjusted_Debt / Adjusted_EBITDA = 3.69x - 3.51x = +0.18x. This falls between -0.2x and +0.2x, so it is **Stable**.
- Signal 2 (Cash-flow coverage): Change in FFO / Adjusted_Debt = 0.1902 - 0.1988 = -0.0086. This falls between -0.03 and +0.03, so it is **Stable**.

Both signals indicate a Stable trend. The company faced massive inflationary headwinds on raw materials in 2022 (nearly doubling), but it successfully passed these costs through to revenues, maintaining proportionate EBITDA growth to its debt expansion and keeping its cash flow coverage relatively flat.

<answer>Stable</answer>