INDEBTEDNESS

Total debt consisted of the following at June 30, 2016, net of unamortized discount and debt issuance cost:



	June 30, 2016		December 31, 2015
6.0% Notes due June 2018	$	200	$	255
7.5% Senior Notes due November 2018	524		747
3.2% Senior Notes due August 2021	511		746
8.55% Debentures due June 2024	112		149
6.875% Notes due January 2029	302		394
5.125% Notes due September 2040	1,132		1,482
Other debt	245		268
Total debt	3,026		4,041
Less: short-term debt and current portion of long-term debt	139		151
Total long-term debt	$	2,887	$	3,890

The estimated fair value of total debt at June 30, 2016 and December 31, 2015 was $3,431 million and $4,321 million, respectively, which differs from the carrying amounts of $3,026 million and $4,041 million, respectively, included in our unaudited consolidated condensed balance sheets. The fair value was determined using quoted period end market prices.

In June 2016, we purchased $1.0 billion of the aggregate outstanding principal amount associated with our long-term outstanding notes and debentures, which included portions of each tranche of notes and debentures. Pursuant to a cash tender offer, the purchases resulted in the payment of an early-tender premium, including various fees, of $135 million and a pre-tax loss on the early extinguishment of debt of $142 million, which includes the premium and the write-off of a portion of the remaining original debt issue costs and debt discounts or premiums.

At June 30, 2016, we had a committed revolving credit facility ("credit facility") with commercial banks and a related commercial paper program under which the maximum combined borrowing at any time under both the credit facility and the commercial paper program was $2.5 billion. The credit facility had a maturity date in September 2016. There were no direct borrowings under the credit facility during the first six months of 2016, and we were in compliance with all of the credit facility's covenants. Under the commercial paper program, we may issue from time to time up to $2.5 billion in commercial paper with maturities of no more than 270 days. The amount available to borrow under the credit facility would be reduced by the amount of any commercial paper outstanding. At June 30, 2016, we had no borrowings outstanding under the commercial paper program.

On July 13, 2016, we entered into a new five-year $2.5 billion committed revolving credit facility (the "2016 Credit Agreement") with commercial banks maturing in July 2021, which replaced our existing credit facility of $2.5 billion, but maintained the existing commercial paper program. The 2016 Credit Agreement contains certain covenants, which, among other things, require the maintenance of a total debt-to-total capitalization ratio, restrict certain merger transactions or the sale of all or substantially all of our assets or a significant subsidiary and limit the amount of subsidiary indebtedness. Upon the occurrence of certain events of default, our obligations under the 2016 Credit Agreement may be accelerated. Such events of default include payment defaults to lenders under the 2016 Credit Agreement, covenant defaults and other customary defaults. To the extent we have outstanding commercial paper, the aggregate ability to borrow under the 2016 Credit Agreement is reduced.