To estimate FFO / Net debt for 2022, use a simplified credit-metrics approach:

1. Estimate FFO  
   A common approximation is:
   - FFO = Cash flow from operating activities before working-capital movements
   - Starting from reported CFO, add back negative working-capital movements or remove positive ones.

   Reported 2022 operating cash flow:
   - Cash flows from operating activities = EUR 10,443 million

   Working-capital adjustments:
   - Decrease/increase in trade and other receivables = -1,701 million
   - Decrease/increase in inventories = +521 million
   - Increase/decrease in trade and other payables = +44 million

   Net working-capital effect:
   - -1,701 + 521 + 44 = -1,136 million

   Since CFO was reduced by EUR 1,136 million due to working capital, add it back:
   - FFO ≈ 10,443 + 1,136 = EUR 11,579 million

2. Estimate net debt  
   Use financial debt and lease liabilities, less cash and cash equivalents.

   Debt-like liabilities at 2022 year-end:
   - Noncurrent borrowings and bonds = 36,129 million
   - Current borrowings and bonds = 10,458 million
   - Noncurrent lease liabilities = 2,287 million
   - Current lease liabilities = 151 million
   - Noncurrent financial instruments with liability characteristics = 576 million
   - Current financial instruments with liability characteristics = 87 million

   Gross debt:
   - 36,129 + 10,458 + 2,287 + 151 + 576 + 87 = EUR 49,688 million

   Cash and cash equivalents:
   - EUR 4,608 million

   Net debt:
   - 49,688 - 4,608 = EUR 45,080 million

3. Calculate FFO / Net debt:
   - 11,579 / 45,080 = 0.2569
   - ≈ 25.7%

<answer>25.7%</answer>