85  / SERVICE EXCELLENCE Contract liabilities 4. Other (income) expense 5. Net interest expense Contract liabilities represent payments received for performance obligations not yet satisfied and relate to deferred revenue and are presented as components of "Accounts payable and accrued liabilities" and "Other long-term liabilities" on the Company's Consolidated Balance Sheets. The following table summarizes the changes in contract liabilities for the years ended December 31, 2019 and 2018: (in millions of Canadian dollars) 2019 2018 Opening balance $ 2 $ 2 Revenue recognized that was included in the contract liability balance at the beginning of the period (2) (2) Increases due to consideration received, net of revenue recognized during the period 146 2 Closing balance $ 146 $ 2 (in millions of Canadian dollars) 2019 2018 2017 Foreign exchange (gain) loss on debt and lease liabilities $ (94 ) $ 168 $ (186 ) Other foreign exchange (gains) losses (4) 3 (7) Insurance recovery of legal settlement — — (10 ) Charge on hedge roll and de-designation — — 13 Other 9 3 12 Other (income) expense $ (89) $ 174 $ (178) (in millions of Canadian dollars) 2019 2018 2017 Interest cost $ 471 $ 475 $ 491 Interest capitalized to Properties (17) (20) (16) Interest expense 454 455 475 Interest income (6) (2) (2) Net interest expense $ 448 $ 453 $ 473 Interest expense includes interest on finance leases of $11 million for the year ended December 31, 2019 (2018 – $11 million; 2017 – $11 million).