Over the second half of 2020, the company took action to reduce our outstanding debt balance. In December 2020, we redeemed our $500 million 4.625 percent notes due in September 2023, and in September 2020, we redeemed our $325 million 3.25 percent notes due in March 2023. Pretax charges of $58 million and $23 million were included in "Interest expense, net of capitalized interest" in the Consolidated Statement of Operations in fourth quarter and third quarter 2020, respectively, for the make-whole premiums, unamortized debt issuance costs and unamortized debt discounts in connection with these early extinguishments.

In March 2020, we issued $750 million of 4.00 percent notes due in April 2030. The net proceeds after deducting the discount, underwriting fees and issuance costs were $732 million. In May 2020, a portion of the net proceeds was used to redeem our $569 million 4.70 percent notes due in March 2021. A net pretax charge of $11 million was included in “Interest expense, net of capitalized interest” in the Consolidated Statement of Operations in second quarter 2020 for the make-whole premium in connection with the early extinguishment, partially offset by the write-off of an unamortized fair value step-up adjustment.

In February 2019, we issued $750 million of 4.00 percent notes due in November 2029. The net proceeds after deducting the discount, underwriting fees and issuance costs were $739 million. In March 2019, a portion of the net proceeds was used to redeem our $500 million 7.38 percent notes due in October 2019. A pretax charge of $12 million was included in "Interest expense, net of capitalized interest" in the Consolidated Statement of Operations in first quarter 2019 for the make-whole premium, unamortized debt issuance costs and unamortized debt discounts in connection with the early extinguishment.

The following table lists our long-term debt by types and interest rates at the end of our last two years and includes the current portion.

DOLLAR AMOUNTS IN MILLIONS
	DECEMBER 31, 2020			DECEMBER 31, 2019
9.00% debentures due 2021		150			150
4.70% debentures due 2021		—			569
7.125% debentures due 2023		191			191
5.207% debentures due 2023		860			860
4.625% notes due 2023		—			500
3.25% debentures due 2023		—			325
8.50% debentures due 2025		300			300
7.95% debentures due 2025		136			136
7.70% debentures due 2026		150			150
7.35% debentures due 2026		62			62
7.85% debentures due 2026		100			100
Variable-rate term loan credit facility matures 2026		225			225
6.95% debentures due 2027		300			300
4.00% notes due 2029		750			750
4.00% notes due 2030		750			—
7.375% debentures due 2032		1,250			1,250
6.875% debentures due 2033		275			275
Other		1			1

Total principal long-term debt		5,500			6,144
Add: fair value adjustments (related to Plum Creek merger)		12			27
Less: unamortized discounts		(28	)		(14	)
Less: unamortized debt expense		(9	)		(10	)
		#REF!
Total	$	5,475		$	6,147

Portion due within one year	$	150		$	—