Debt

Total debt as of December 31 consisted of the following:



(millions)	2017		2016
4.875% senior notes due 2027	$	500	$	—
5.5% senior notes due 2025	350		350
7.75% senior notes due 2018	—		500
Industrial revenue bonds (due 2028 through 2034)	239		239
Total	$	1,089	$	1,089
Less: Unamortized debt issuance costs	11		6
Total	$	1,078	$	1,083

Issuance of Senior Notes

During 2017, we issued $500 million of 4.875% senior notes due 2027, referred to as our 4.875% Notes. The net proceeds from the issuance of these notes and cash on hand were used to fund the repurchase of our 7.75% senior notes due 2018, referred to as our 7.75% Notes, and all related costs and expenses. We deferred $7 million of debt issuance costs that are being amortized to interest expense over the term of the 4.875% Notes.

In 2015, we issued $350 million of 5.5% senior notes due 2025, referred to as our 5.5% Notes. The net proceeds from the issuance of these notes and cash on hand were used to fund the repurchase of our 8.375% senior notes due 2018, referred to as our 8.375% Notes, and all related costs and expenses. We deferred approximately $6 million of debt issuance costs that are being amortized to interest expense over the term of the notes.

Repurchases and Redemptions of Senior Notes

During 2017, we repurchased $500 million of our 7.75% Notes through a cash tender offer and subsequent redemption for aggregate consideration of $536 million, including premiums of $20 million and accrued interest of $16 million. For the year ended December 31, 2017, we recorded a pre-tax loss on the early extinguishment of debt of $21 million.

During 2016, we repaid $500 million of our 6.3% senior notes due 2016, referred to as the 6.3% Notes, $250 million of our 7.875% senior notes due 2020, referred to as the 7.875% Notes, and $350 million of our 5.875% senior notes due 2021, referred to as the 5.875% Notes. The retirement of the 6.3% Notes, the 7.875% Notes and the 5.875% Notes included premiums of $30 million and accrued interest of $9 million. As a result of these transactions, we recorded a loss on the early extinguishment of debt, before tax, of $37 million including premiums, write-off of deferred financing fees, debt discount and broker fees.

During 2015, we repurchased $350 million of our 8.375% Notes, through a cash tender offer and subsequent redemption for aggregate consideration, including tender offer premium and accrued and unpaid interest, of $377 million. As a result of the repurchases, we recorded a loss on the early extinguishment of debt of $19 million including the write-off of unamortized debt issuance costs.

Senior Notes

Our senior notes are senior unsecured obligations, rank equally with all of our other existing and future unsecured senior indebtedness and are guaranteed by certain of our domestic subsidiaries. The indentures governing the notes contain events of default, covenants and restrictions that are customary for similar securities, including a limitation on our ability and the ability of certain of our subsidiaries to create or incur secured indebtedness.



Interest rate	5.5%	4.875%
Principal net of discount (in millions) ^(a)	$350	$500
Maturity	March 1, 2025	June 1, 2027
Call date ^(b)	March 1, 2020	June 1, 2022
Mandatory redemption offer	at 101% plus accrued and unpaid interest in the event of a change in control	at 101% plus accrued and unpaid interest in the event of a change in control


(a)	Principal amounts exclude unamortized debt issuance costs.

(b)

Callable at any time, in whole or in part, prior to the call date at a redemption price equal to 100% of the principal plus a premium (as outlined in the respective indentures), plus any accrued and unpaid interest on the principal amount being called. Callable after the call date at stated redemption prices (as outlined in the applicable indenture), plus any accrued and unpaid interest on the principal amount being called.

Credit Facility

In 2017, we amended and restated our credit facility agreement to, among other things, increase the maximum borrowing limit from $180 million to $220 million. As a result, we recorded a pre-tax loss on extinguishment of debt of $1 million for the year ended December 31, 2017 and incurred $1 million of debt issuance costs. Our amended and restated agreement requires us to maintain a minimum fixed charge coverage ratio in the event excess availability falls below a minimum threshold. Because our excess borrowing availability as of December 31, 2017 of $155 million exceeds this threshold, the requirement to maintain the minimum fixed charge coverage ratio is not applicable. As of December 31, 2017, we were in compliance with the covenants contained in our credit facility.

As of December 31, 2017 and during the year then ended, there were no borrowings under the facility. Outstanding letters of credit as of December 31, 2017 totaled $29 million.

Industrial Revenue Bonds

Our $239 million of industrial revenue bonds have fixed interest rates ranging from 5.5% to 6.4%. The weighted average rate of interest on our industrial revenue bonds is 5.875%. These bonds mature during the years 2028 through 2034.

OTHER INFORMATION



(millions)	December 31, 2017		December 31, 2016
Fair value of debt	$	1,134	$	1,129
Accrued interest	12		31

The fair value of our debt was determined using the fair value hierarchy of inputs described in Note 1. The fair values were determined utilizing prices from independent pricing services. The vendors’ methodologies utilize various forms of market data, including but not limited to, trade data, yield, spreads, bids and offers. We review the values provided by the independent pricing service for reasonableness by comparing the valuations received from the independent pricing service to valuations from at least one other observable source. We have not adjusted the prices obtained from the independent pricing service. As a result, the fair values are classified as Level 2. See Note 8 for further discussion on fair value measurements.

As of December 31, 2017, the amounts of total debt outstanding maturing in each of the next five years and beyond were as follows:



(millions)	2018 through 2022		After 2022
Debt maturities (principal amounts)	$	—	$	1,089