Note 6—LONG-TERM DEBT

In November 2012, we issued $3.0 billion of unsecured senior notes in three tranches as described in the table below (collectively, the “Notes”). The net carrying amount of the Notes was $3.0 billion and the unamortized discount was $27 million at December 31, 2012. We also have other long-term debt with a carrying amount, including the current portion, of $691 million and $384 million at December 31, 2012 and 2011. The face value of our total long-term debt obligations is as follows (in millions):

The effective interest rates of the 2015, 2017, and 2022 Notes were 0.84%, 1.38%, and 2.66%. Interest on the Notes is payable semi-annually in arrears in May and November. We may redeem the Notes at any time in whole, or from time to time, in part at specified redemption prices. We are not subject to any financial covenants under the Notes. We used the net proceeds from the issuance of the Notes for general corporate purposes. The estimated fair value of the Notes was approximately $3.0 billion at December 31, 2012, which is based on quoted prices for our publicly-traded debt as of that date.

The other debt, including the current portion, had a weighted average interest rate of 6.4% and 5.9% in 2012 and 2011. We used the net proceeds from the issuance of the debt to fund certain international operations. The estimated fair value of the other long-term debt, which is based on Level 2 inputs, approximated its carrying value at December 31, 2012 and December 31, 2011.

At December 31, 2012, future principal payments for debt were as follows (in millions):