To estimate the Funds From Operations (FFO) to Net Debt ratio for ENI S.P.A. at the end of 2022, we first calculate both FFO and Net Debt based on the provided facts.

**1. Funds From Operations (FFO)**
FFO is typically calculated as Cash Flow from Operating Activities (CFO) before the impact of changes in working capital. 
From the data:
- "Cash Flows From Used In Operating Activities" (CFO) = 17,460,000,000 EUR
- "Increase Decrease In Working Capital" = 1,279,000,000 EUR. Checking the individual working capital adjustments (Inventories: -2,528m, Receivables: -1,036m, Payables: +2,284m, Provisions: +2,028m, Other Assets/Liabilities: -2,027m, Employee Benefits: +39m), the sum represents a net cash outflow of roughly 1,279,000,000 EUR. Because this working capital increase consumed cash, we must add it back to CFO to find the cash generated before working capital changes.
FFO = CFO - Cash Flow from Working Capital Changes 
FFO = 17,460,000,000 - (-1,279,000,000) = 18,739,000,000 EUR

**2. Net Debt**
Net Debt is calculated as Total Debt (including lease liabilities) minus Cash and Cash Equivalents, and highly liquid Short-Term Investments (which ENI includes in its net borrowings definition).
*Total Debt:*
- "Shortterm Borrowings": 4,446,000,000 EUR
- "Current Portion Of Longterm Borrowings": 3,097,000,000 EUR
- "Current Lease Liabilities": 884,000,000 EUR
- "Longterm Borrowings": 19,374,000,000 EUR
- "Noncurrent Lease Liabilities": 4,067,000,000 EUR
Total Debt = 4,446 + 3,097 + 884 + 19,374 + 4,067 = 31,868,000,000 EUR

*Cash & Short-Term Investments:*
- "Cash And Cash Equivalents": 10,155,000,000 EUR
- "Current Financial Assets At Fair Value Through Profit Or Loss" (highly liquid securities): 8,251,000,000 EUR
- "Other Current Financial Assets" (short-term financing receivables): 1,504,000,000 EUR
Total Liquid Assets = 10,155 + 8,251 + 1,504 = 19,910,000,000 EUR

Net Debt = Total Debt - Total Liquid Assets
Net Debt = 31,868,000,000 - 19,910,000,000 = 11,958,000,000 EUR

**3. FFO / Net Debt Ratio**
Ratio = FFO / Net Debt
Ratio = 18,739,000,000 / 11,958,000,000 ≈ 1.567

<answer>1.57</answer>