FFO / Net debt under an S&P-style approximation can be estimated as:

**1. Funds from operations (FFO)**  
A common approximation is:

FFO = Cash flow from operations before working capital changes

Given:
- Cash flows from operations = 548,169,000
- Increase/decrease in working capital = -336,750,000

So:

FFO = 548,169,000 - (-336,750,000)  
FFO = 884,919,000

**2. Net debt**  
Approximate gross financial debt as current plus non-current financial liabilities, including other financial liabilities:

- Short-term financial liabilities = 142,437,000
- Other current financial liabilities = 290,000
- Long-term financial liabilities = 6,402,913,000
- Other non-current financial liabilities = 34,000

Gross debt = 142,437,000 + 290,000 + 6,402,913,000 + 34,000  
Gross debt = 6,545,674,000

Subtract cash and cash equivalents:

- Cash and cash equivalents = 451,946,000

Net debt = 6,545,674,000 - 451,946,000  
Net debt = 6,093,728,000

**3. FFO / Net debt**

FFO / Net debt = 884,919,000 / 6,093,728,000  
FFO / Net debt = 0.1452, or about 14.5%

<answer>14.5</answer>