As of December 31, 2017, we carried a total debt balance (including accrued interest) of €4,823.9 million, of which €2,211.8 million principal amount is related to the Senior Secured Fixed Rate Notes with maturities ranging from 2024 through 2028 and €1,811.4 million principal amount is owed under our 2017 Amended Senior Credit Facility. Our total debt balance at December 31, 2017 also included €262.6 million of short-term debt related to our vendor financing program and €16.3 million for the outstanding portion of the 3G mobile spectrum including accrued interest. The remainder primarily represents the capital lease obligations associated with the Interkabel Acquisition.
In April 2017, we successfully syndicated and priced a new €1.33 billion Term Loan facility ("Facility AH") due on March 31, 2026 and a new USD 1.8 billion Term Loan facility ("Facility AI") due on June 30, 2025. Facility AH carries a margin of 3.0% over EURIBOR with a 0% floor and was issued at 99.75% of par. Facility AI carries a margin of 2.75% over LIBOR with a 0% floor and was issued at 99.75% of par. The net proceeds of these issuances were used in May 2017 to entirely prepay the following credit facilities under our 2015 Amended Senior Credit Facility: (i) Facility AE (€1.6 billion due January 2025, EURIBOR +3.25%, 0% floor), and (ii) Facility AF (USD 1.5 billion due January 2025, LIBOR + 3.00%, 0% floor).
In May 2017, we successfully issued an additional USD 500.0 million Term Loan (“Facility AI2”). Facility AI2 carries the same characteristics as the initial Facility AI which was issued on April 4, 2017. As such, Facility AI2 carries (i) a margin of 2.75% over LIBOR, (ii) a 0% floor and (iii) a maturity of June 30, 2025. Term Loan AI2 was issued at par and has been merged into the initial Facility AI. The net proceeds were used mid-June 2017 to prepay the 6.25% €450.0 million Senior Secured Notes due August 2022. Through the two aforementioned transactions, we succeeded in extending the average tenor of our debt maturities at attractive market conditions, while locking in long-term attractive interest rates.
In June 2017, we drew €210.0 million under our revolving credit facilities to partially fund the acquisition of SFR Belux of which €120.0 million under our RCF Z and the remaining €90.0 million under our longer-dated RCF AG. In Q3 and Q4 2017, we used our excess cash balance to fully repay the drawn commitments under the aforementioned revolving credit facilities, while we also cancelled the freed commitments under our short-dated RCF Z.
ln December 2017, we successfully issued €600.0 million and USD 1.0 billion Senior Secured Fixed Rate Notes due 2028 at par. The Notes will mature on March 1, 2028 and carry a fixed coupon of 3.50% and 5.50%, for the €-denominated Notes and USD-denominated Notes respectively, due on a semi-annual basis as of mid-January 2018. On the back of strong investor demand, Telenet was able to significantly upsize both the €-denominated and USD-denominated Notes from the €500.0 million and USD 750.0 million initial size, as such successfully tapping the USD high-yield market for the first time. In addition, we successfully syndicated a new €730.0 million Term Loan facility (“Facility AM”) and a new USD 1.3 billion Term Loan facility (“Facility AL”), due respectively on December 15, 2027 and March 1, 2026. Facility AL carries a margin of 2.50% over LIBOR with a 0% floor and was issued at par. Facility AM carries a margin of 2.75% over EURIBOR with a 0% floor and was issued at par. The net proceeds from these four new facilities were used to entirely prepay the following credit facilities under its Senior Credit Facility: (i) Facility AH (€1.33 billion due March 2026, EURIBOR +3.00%, 0% floor); and (ii) Facility AI (USD 2.3 billion due June 2025, LIBOR + 2.75%, 0% floor). Through this transaction, we succeeded in extending the average tenor of our debt maturities from 8.1 years pre-refinancing to 9.4 years post-refinancing at attractive rates, while ensuring increased covenant flexibility going forward.
In December 2017, we also entered into a new three-year €20.0 million revolving credit facility with availability up to September 30, 2021. This new revolving credit facility can be used for general corporate purposes of our group and carries a margin of 2.0% over EURIBOR (0% floor).We face no debt maturities prior to August 2024 and as of December 31, 2017, have full access to €445.0 million of undrawn commitments under our revolving credit facilities with certain availabilities up to June 30, 2023.