	2019			2018
Borrowings under the ABL Credit Facility	$	42.0		$	59.0
11.25% senior notes due February 1, 2019^(a)		—			172.2
7.625% senior notes due June 15, 2020		65.8			65.8
7.875% senior notes due March 15, 2021		167.1			190.4
8.875% debentures due April 15, 2021		60.2			81.0
7.00% senior notes due February 15, 2022		140.0			140.0
6.50% senior notes due November 15, 2023		290.6			290.6
Term Loan due January 15, 2024 ^(b)		540.3			544.7
6.00% senior notes due April 1, 2024		298.3			298.3
6.625% debentures due April 15, 2029		157.9			157.9
8.820% debentures due April 15, 2031		69.0			69.0
Other ^(c)		—			38.9
Unamortized debt issuance costs		(12.8	)		(16.3	)
Total debt		1,818.4			2,091.5
Less: current portion		71.2			216.2
Long-term debt	$	1,747.2		$	1,875.3

(a)	As of December 31, 2018 the interest rate on the 11.25% senior notes due February 1, 2019 had contractually increased to 13.25%.

(b)	As of December 31, 2019 and 2018, the interest rate on the Term Loan due January 15, 2024 was 6.80% and 7.51%, respectively.

(c)	Includes miscellaneous debt obligations.

The fair values of the senior notes and debentures, which were determined using the market approach based upon quoted prices or interest rates available to us for debt obligations with similar terms and maturities, were determined to be Level 2 under the fair value hierarchy. The fair value of our total debt was greater than its book value by approximately $29.3 million at December 31, 2019 and less than its book value by approximately $14.4 million at December 31, 2018.

During the year ended December 31, 2019, we repurchased on the open market $23.4 million and $20.7 million in aggregate principal amount of the 7.875% senior notes due 2021 and 8.875% debentures due 2021, respectively. We recorded a loss on debt extinguishment of $0.8 million in the third quarter of 2019 on the repurchase of the notes and debentures.

On February 1, 2019, we retired the $172.2 million 11.25% senior notes using availability under our ABL Credit Facility.

On October 15, 2018, we entered into a $550.0 million senior secured term loan B (the “Term Loan”) pursuant to a credit agreement (the “Term Loan Credit Agreement”). Proceeds from the Term Loan, net of a $5.5 million discount, were used to repurchase certain senior notes, pay transaction fees and repay a portion of borrowings under the ABL Credit Facility. The Term Loan is scheduled to mature on January 15, 2024, at which time the remaining outstanding balance under the Term Loan will be due and payable. Principal payments of $1.4 million are due quarterly. The Term Loan bears interest based on the London Interbank Offered Rate (LIBOR) plus a margin of 5% or a base rate plus a margin of 4%.

On October 15, 2018, we repurchased $172.6 million and $257.4 million in aggregate principal amount of the 7.625% senior notes due 2020 and 7.875% senior notes due 2021, respectively, pursuant to a tender offer. We recorded a loss on debt extinguishment of $32.3 million in the fourth quarter of 2018 on the repurchase of the bonds, representing tender premiums paid of $29.0 million, write-off of unamortized debt issuance costs of $1.5 million and fees and expenses of $1.8 million.

We entered into an $800.0 million senior secured asset-based revolving credit facility (the “ABL Credit Facility”) on September 29, 2017, pursuant to a credit agreement (the “ABL Credit Agreement”), which replaced our prior $800.0 million senior secured revolving credit facility dated September 30, 2016.

On October 15, 2018, we amended the ABL Credit Agreement to, among other things, permit (i) the incurrence of the debt pursuant to the Term Loan Credit Agreement and (ii) the incurrence of a lien on the ABL Priority Collateral (described below) to secure our obligations under the Term Loan Credit Agreement and related guarantees on a second-priority basis. The ABL Credit Facility is scheduled to mature on September 29, 2022, at which time all outstanding amounts under the ABL Credit Facility will be due and payable.

The amount available to be borrowed under the ABL Credit Facility is equal to the lesser of (a) $800.0 million and (b) a borrowing base formula based on the amount of accounts receivable, inventory, machinery, equipment and, if we were to so elect in the future subject to the satisfaction of certain conditions, fee-owned real estate of ours and our material domestic subsidiaries, subject to certain eligibility criteria and advance rates (collectively, the “Borrowing Base”). The aggregate amount of real estate, machinery and equipment that can be included in the Borrowing Base formula cannot exceed $200.0 million.

Borrowings under the ABL Credit Facility bear interest at a rate dependent on the average quarterly availability and is calculated according to a base rate (except in certain circumstances, based on the prime rate) or a Eurocurrency rate (except in certain circumstances, based on LIBOR) plus an applicable margin. The applicable margin for base rate loans ranges from 0.25% to 0.50% and the applicable margin for Eurocurrency loans ranges from 1.25% to 1.50%. In addition, a fee is payable quarterly on the unused portion of the total commitments. This fee accrues at a rate of either 0.25% or 0.375% depending upon the average usage of the facility. Borrowings under the ABL Credit Facility may be used for working capital and general corporate purposes.

Based on our Borrowing Base as of December 31, 2019 and existing borrowings, we had approximately $633.7 million of borrowing capacity available under the ABL Credit Facility. The weighted average interest rate on borrowings under our ABL Credit Facility was 3.7%, 3.5%, 3.5% for the years ended December 31, 2019, 2018 and 2017, respectively.

Our obligations under the ABL Credit Facility are guaranteed by our material domestic subsidiaries (the “Guarantors”) and are secured by a security interest in substantially all assets of ours and the Guarantors, including, only to the extent included in the Borrowing Base, real property, in each case subject to certain exceptions and exclusions. The assets of ours and the Guarantors consisting of accounts receivable, inventory, deposit accounts, securities accounts, machinery and equipment and, to the extent related to the foregoing, general intangibles, documents and instruments, as well as 65% of the equity interests of our first-tier foreign subsidiaries (collectively, the “ABL Priority Collateral”), secure our obligations and the obligations of the Guarantors under the ABL Credit Facility and the related guarantees on a first-priority basis, and all other collateral other than the ABL Priority Collateral secures our obligations and the obligations of the Guarantors under the ABL Credit Facility on a second-priority basis, in each case, subject to permitted liens.

Our obligations under the Term Loan Credit Agreement are guaranteed by the Guarantors and are secured by a security interest in substantially all assets of ours and the Guarantors, including certain material real property, subject to certain exceptions and exclusions. The ABL Priority Collateral secures our obligations and the obligations of the Guarantors under the Term Loan Credit Agreement and related guarantees on a second-priority basis, and all other collateral other than the ABL Priority Collateral secures our obligations and the obligations of the Guarantors under the Term Loan Credit Agreement and related guarantees on a first-priority basis, in each case, subject to permitted liens.

The ABL Credit Agreement and Term Loan Credit Agreement contain customary affirmative and negative covenants including negative covenants restricting, among other things, our ability to incur debt, make investments, make certain restricted payments (including payments on certain other debt and external dividends), incur liens securing other debt, consummate certain fundamental transactions, enter into transactions with affiliates and consummate asset sales. The ABL Credit Agreement contains a covenant which requires us to maintain a minimum fixed charge coverage ratio of 1.0 to 1.0 if availability under the ABL Credit Facility declines below certain levels. The Term Loan Credit Agreement requires that the net cash proceeds of significant asset sales be used to prepay the Term Loan to the extent that the net cash proceeds are not used for reinvestment in assets useful to our business, certain acquisitions and investments, repayment of certain borrowings under our ABL Credit Facility or the funding of debt repayments, redemptions or tenders of certain existing notes maturing prior to the maturity of the Term Loan, in each case, subject to certain restrictions and limitations set forth in the Term Loan Credit Agreement.

On June 7, 2017, we repurchased $41.7 million of the 6.625% debentures due April 15, 2029, $59.4 million of the 6.50% senior notes due November 15, 2023 and $101.7 million of the 6.00% senior notes due April 1, 2024 using borrowings under the prior credit agreement. The repurchases resulted in a net gain of $0.8 million which was recognized within loss on debt extinguishment in the Consolidated Statements of Operations for the year ended December 31, 2017 related to the difference between the fair value of the debt repurchased and the principal outstanding, partially offset by the premiums paid, unamortized debt issuance costs and other expenses.

On May 22, 2017, certain third party financial institutions (such financial institutions collectively, the “Third Party Purchasers”), launched cash tender offers for certain of our outstanding debt securities, including our 7.625% senior notes due June 15, 2020 and 7.875% senior notes due March 15, 2021. On June 7, 2017, the Third Party Purchasers purchased $111.6 million in aggregate principal amount of the 7.625% senior notes due June 15, 2020 (the “Third Party Purchase Notes”). On June 21, 2017, we exchanged 6.1 million of our retained shares of Donnelley Financial for the Third Party Purchase Notes. We cancelled the Third Party Purchase Notes on June 21, 2017. As a result, we recognized a $14.4 million loss on debt extinguishment in the Consolidated Statements of Operations during the year ended December 31, 2017 related to premiums paid, unamortized debt issuance costs and other expenses. In addition, we recognized a net realized gain of $92.4 million resulting from the disposition of these retained shares of Donnelley Financial common stock within net investment and other income in the Consolidated Statements of Operations during the year ended December 31, 2017.

On August 4, 2017, we disposed of our remaining 0.1 million shares of Donnelley Financial common stock in exchange for $1.9 million in aggregate principal of our 7.875% senior notes due March 15, 2021 which were cancelled. As a result, we recognized a $0.3 million loss on debt extinguishments in the Consolidated Statements of Operations during the year ended December 31, 2017, related to premiums paid, unamortized debt issuance costs and other expenses. In addition, we recognized a net realized gain of $1.6 million resulting from the disposition of these retained shares of Donnelley Financial common stock within net investment and other income in the Consolidated Statements of Operations during the year ended December 31, 2017.

As of December 31, 2019, we had $42.0 million of borrowings and $39.1 million of letters of credit issued under the ABL Credit Facility. We also had $137.0 million in other uncommitted credit facilities, primarily outside the U.S. (the “Other Facilities”), of which we had $87.6 million in outstanding letters of credit, bank guarantees and bank acceptance drafts.

	Amount
2020	$	71.3
2021		233.0
2022		187.5
2023		296.1
2024		820.7
2025 and thereafter		227.3
Total ^(a)	$	1,835.9

(a)	Excludes unamortized debt issuance costs of $12.8 million and $4.7 million of bond discount which do not represent contractual commitments with a fixed amount or maturity date.

The following table summarizes interest expense included in the Consolidated Statements of Operations:

	2019		2018		2017
Interest incurred	$	155.7	$	173.8	$	185.0
Less: interest income		2.7		4.2		2.8
Less: interest capitalized as property, plant and equipment		2.4		1.3		2.6
Interest expense, net	$	150.6	$	168.3	$	179.6

Interest paid was $158.6 million, $173.0 million and $180.1 million for the years ended December 31, 2019, 2018 and 2017, respectively.