| Supplemental Financial Information |
Supplemental Financial Information Interest Expense, Net | | | | | | | | | | | | | | | | | | | years ended December 31 (in millions) | 2020 | | 2019 | | 2018 | | Interest expense | $ | 2,454 | | | $ | 1,784 | | | $ | 1,348 | | | Interest income | (174) | | | (275) | | | (204) | | | Interest expense, net | $ | 2,280 | | | $ | 1,509 | | | $ | 1,144 | |
Accounts Payable and Accrued Liabilities | | | | | | | | | | | | | as of December 31 (in millions) | 2020 | | 2019 | | Sales rebates | $ | 7,188 | | | $ | 4,484 | | | Dividends payable | 2,335 | | | 1,771 | | | Accounts payable | 2,276 | | | 1,452 | | | Salaries, wages and commissions | 1,669 | | | 830 | | | Royalty and license arrangements | 483 | | | 324 | | | Other | 6,208 | | | 2,971 | | | Accounts payable and accrued liabilities | $ | 20,159 | | | $ | 11,832 | |
Other Long-Term Liabilities | | | | | | | | | | | | | as of December 31 (in millions) | 2020 | | 2019 | | Contingent consideration liabilities | $ | 12,289 | | | $ | 7,201 | | | Liabilities for unrecognized tax benefits | 5,680 | | | 2,772 | | | Income taxes payable | 3,847 | | | 3,453 | | | Pension and other post-employment benefits | 3,413 | | | 2,949 | | | Other | 2,378 | | | 1,222 | | | Other long-term liabilities | $ | 27,607 | | | $ | 17,597 | |
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