Long-Term Debt Maturities

Note 9: Long-Term Debt

As of December 31, 2013 and 2012, our debt had an estimated fair value of $51.8 billion and $47.7 billion, respectively. The estimated fair value of our publicly traded debt is based on quoted market values for the debt. To estimate the fair value of debt for which there are no quoted market prices, we use interest rates available to us for debt with similar terms and remaining maturities. See Note 21 for additional information on our subsidiary guarantee structures.

Redemption Transaction

The Redemption Transaction resulted in the consolidation of an additional $4 billion aggregate principal amount of senior notes issued by NBCUniversal Enterprise and $1.25 billion of borrowings under the NBCUniversal Enterprise credit facility. The total consideration for the Redemption Transaction also included $750 million of cash funded through our commercial paper program.

The NBCUniversal Enterprise senior notes are comprised of $1.1 billion aggregate principal amount of 1.662% senior notes due 2018, $1.5 billion aggregate principal amount of 1.974% senior notes due 2019, $700 million aggregate principal amount of floating rate senior notes due 2016 and $700 million aggregate principal amount of floating rate senior notes due 2018. The floating rate senior notes due 2016 and 2018 will accrue interest for each quarterly interest period at a rate equal to three-month London Interbank Offered Rate (“LIBOR”) plus 0.537% and 0.685%, respectively.

On March 19, 2013, NBCUniversal Enterprise amended and restated the existing credit agreement of NBCUniversal to, among other things, substitute NBCUniversal Enterprise for NBCUniversal as the sole borrower, reduce the borrowing capacity of the facility from $1.5 billion to $1.35 billion, extend the term of the facility to March 2018 and revise the interest rate on borrowings. The interest rate on the credit facility consists of a base rate plus a borrowing margin that is determined based on our credit rating. Following the amendments to this credit agreement, NBCUniversal's commercial paper program was terminated. As of December 31, 2013, $1.25 billion was outstanding under this credit facility.

Debt Instruments

Revolving Credit Facilities

As of December 31, 2013, Comcast Corporation and Comcast Cable Communications, LLC had a $6.25 billion revolving credit facility due June 2017 with a syndicate of banks. The interest rate on this facility consists of a base rate plus a borrowing margin that is determined based on our credit rating. As of December 31, 2013, the borrowing margin for LIBOR-based borrowings was 1.00%. This revolving credit facility requires that we maintain certain financial ratios based on our debt and our operating income before depreciation and amortization, as defined in the credit facility. We were in compliance with all financial covenants for all periods presented.

As of December 31, 2013, amounts available under our consolidated credit facilities, net of amounts outstanding under our commercial paper program and outstanding letters of credit, totaled $4.7 billion, which included $100 million available under NBCUniversal Enterprise's credit facility.

Commercial Paper Program

Our commercial paper program provides a lower cost source of borrowing to fund our short-term working capital requirements and is supported by our $6.25 billion revolving credit facility due June 2017. In September 2013, we increased the borrowing capacity of our commercial paper program from $2.25 billion to $6.25 billion.

Letters of Credit

As of December 31, 2013, we and certain of our subsidiaries had unused irrevocable standby letters of credit totaling $515 million to cover potential fundings under various agreements.