An out of period adjustment was included in the year ended December 31, 2018 to reduce Goodwill and increase Accumulated other comprehensive loss by $180 million attributed to goodwill from prior acquisitions of foreign entities previously not recorded in the correct local currency. The adjustment did not impact the consolidated results of operations and was not material to previously reported balance sheets. Amortization expense of other intangible assets was $198 million in 2018, $190 million in 2017 and $178 million in 2016. Future annual amortization expense of other intangible assets is expected to be approximately $230 million in 2019, $190 million in 2020, $160 million in 2021, $130 million in 2022, and $100 million in 2023. Other intangible asset impairment charges were $84 million in 2018, $80 million in 2017 and $33 million in 2016. In 2018, a $64 million impairment charge was recorded in Other income (net) for an out-licensed asset obtained in the 2010 acquisition of ZymoGenetics, Inc., which did not meet its primary endpoint in a Phase II clinical study. A $75 million IPRD charge was recognized and attributed to noncontrolling interest after BMS declined to exercise its option to purchase F-Star in 2017. Note 14. ACCRUED LIABILITIES December 31, Dollars in Millions 2018 2017 Rebates and returns $ 2,417 $ 2,024 Employee compensation and benefits 848 869 Research and development 805 783 Dividends 669 654 Royalties 391 285 Branded Prescription Drug Fee 188 303 Liabilities related to assets held-for-sale 152 — Litigation and other settlements 118 38 Restructuring 85 155 Pension and postretirement benefits 35 40 Other 781 863 Accrued liabilities $ 6,489 $ 6,014 88