Restructuring and Other Charges. Restructuring and other charges were $182 in 2020 compared with $582 in 2019 and $163 in 2018. 

Restructuring and other charges in 2020 consisted primarily of a $113 charge for layoff costs, a $74 charge for U.K. and U.S. pension plans' settlement accounting; a $5 post-closing adjustment related to the sale of the Company’s U.K. forgings business; a $5 charge for impairment of assets associated with an agreement to sell an aerospace components business in the U.K that did not occur and the business was returned to held for use; $5 charge related to the impairment of a cost method investment, which were partially offset by a benefit of $21 related to the reversal of a number of prior period programs; 

Restructuring and other charges in 2019 consisted primarily of a $428 charge for impairment of the Disks long-lived asset group; a $69 charge for layoff costs ; a $46 charge for impairment of assets associated with an agreement to sell the U.K. forgings business; a $14 charge for impairment of properties, plants, and equipment related to the Company’s primary research and development facility; a $13 loss on sale of assets primarily related to a small additive business; a $12 charge for other exit costs from lease terminations primarily related to the exit of the corporate aircraft; a $9 settlement accounting charge for U.S. pension plans; a $5  charge for impairment of a cost method investment; an d a $7 charge for other exit costs; which were partially offset by a benefit of $ 16 related to the elimination of the life insurance benefit for the U.S. sal aried and non-bargaining hourly retirees of the Company and its subsidiaries. 

Restructuring and other charges in 2018 consisted primarily of a $9 6 charge for pension plan settlement accounting; a $23 charge for pension curtailment; a $43 loss on sale of a Hungary forgings business; a $18 charge for layoff costs; a $12 charge for contract termination costs and asset impairments associated with the shutdown of a facility in Acuna, Mexico; which were offset partially by a $28 postretirement curtailment benefit. 

See Note E  to the Consolidated Financial Statements in Part II, Item 8. (Financial Statements and Supplementary Data) of this Form 10-K. 

Interest Expense. Interest expense was $381 in 2020 compared with $338 in 2019. The increase of $43, or 13%, was primarily due to premiums paid on the early redemption of debt of $59 which was offset by lower debt outstanding in 2020 driven by the early redemption of $1,000, $889 and $151 of the principal amount of the 6.150% Notes, 5.400% Notes due in 2021 and 5.870% Notes due in 2022, respectively, in April and May 2020, which was offset by the issuance on April 24, 2020 of the 6.875% Notes due 2025 in the aggregate principal amount of $1,200. 

Interest expense was $338 in 2019 compared with $377 in 2018. The decrease of $39, or 10%, was primarily due to lower debt outstanding, driven by the repayment of the aggregate outstanding principal amount of the 1.63% Convertible Notes of approximately $403 on October 15, 2019, as well as costs incurred of $19 in 2018 related to the premium paid on the early redemption of the Company’s then outstanding 5.72% Senior Notes due in 2019 that did not recur in 2019. 

On January 15, 2021, the Company completed the early redemption of all of the remaining $361 aggregate principal amount of the 5.400% Notes due in April 2021 (the "5.400% Notes") as well as $5 in accrued interest. The redemption of these 5.400% Notes will save approximately $5 in Interest expense, net in the first quarter of 2021 and $19 annually. 

Other Expense (Income), Net. Other expense (income), net was $74 in 2020 compared with $31 in 2019. The increase in expense of $43 was primarily driven by the write-off of an indemnification receivable related to a Spanish tax reserve reflecting Alcoa Corporation's 49% share and Arconic Corporation's 33.66% share of a Spanish tax reserve of $53 and lower interest income of $19, which were partially offset by lower deferred compensation expense of $14 and favorable foreign currency movements of $16. 

Other expense (income), net was $31 in 2019 compared with Other expense (income), net of $(30) in 2018. The increase in Other expense, net of $61 was primarily due to an increase in deferred compensation expense of $32 and the benefit recognized in 2018 from establishing a tax indemnification receivable reflecting Alcoa Corporation’s 49% share of a Spanish tax reserve of $29. 

Income Taxes. Howmet’s effective tax rate was 23.4% (benefit on pre-tax income) in 2020 compared with the U.S. federal statutory rate of 21%. The effective rate differs from the U.S. federal statutory rate primarily as a result of a $64 benefit related to the release of an income tax reserve following a favorable Spanish tax case decision, a $30 benefit related to the recognition of a previously uncertain U.S. tax position, and a $30 benefit for a U.S. tax law change related to the issuance of final regulations that provide for an exclusion of certain high-taxed foreign earnings from the calculation of Global Intangible Low-Taxed Income ("GILTI"), partially offset by U.S. tax on foreign earnings, $8 of charges related to the remeasurement of deferred tax balances as a result of the Arconic Inc. Separation Transaction, the tax impact of $49 of nondeductible loss related to the reversal of indemnification receivables associated with the favorable Spanish tax case decision, and the tax impact of other nondeductible expenses. 

Howmet’s effective tax rate was 40.0% (provision on pre-tax income) in 2019 compared with the U.S. federal statutory rate of 21%. The effective rate differs from the U.S. federal statutory rate primarily as a result of foreign income taxed in higher rate 

