Contractual Obligations and Other Commercial Commitments Item 7A. Quantitative and Qualitative Disclosures About Market Risk We evaluate the effects of changes in foreign currency exchange rates, interest rates and other relevant market risks on our derivatives. We periodically determine the potential loss from market risk on our derivatives by performing a value-at-risk analysis, or VaR. VaR is a statistical model that uses historical currency exchange rate data to measure the potential impact on future earnings of our derivative financial instruments assuming normal market conditions. The VaR model is not intended to represent actual losses but is used as a risk estimation and management tool. Based on the results of the model, we estimate with We manage our exposure to foreign exchange and interest rate risk through various strategies, including the use of derivative financial instruments. We use forward foreign exchange contracts as economic hedges to manage the cash flow volatility arising from foreign exchange rate fluctuations. We may use interest rate swaps to manage our interest expense and structure our long-term debt portfolio to achieve a mix of fixed rate and floating rate debt. We do not use derivatives for trading or speculative purposes. Using derivatives exposes us to the risk that counterparties to the derivative contracts will fail to meet their contractual obligations. We manage that risk through careful selection and ongoing evaluation of the counterparty financial institutions based on specific minimum credit standards and other factors. At December 31, 2019, there were no significant off-balance sheet arrangements. At December 31, 2019, our commercial commitments were (in millions): At December 31, 2019, the unfunded benefit obligation for our defined benefit pension plans and postemployment arrangements was $375.2 million. In 2019, we contributed $7.1 million to our defined benefit pension plans and paid $7.8 million in benefits for our postemployment arrangements. We do not expect these payments to increase significantly in 2020. The liability for uncertain tax positions is subject to uncertainty as to when or if the liability will be paid. We have assigned the liability to the periods presented based on our judgment as to when these liabilities will be resolved by the appropriate taxing authorities. The liability for the transition tax on accumulated foreign earnings is payable through 2026. See Note 11 to the consolidated financial statements for additional information. Certain acquisitions include an initial payment at closing and provide for future additional contingent purchase price payments (earn-outs) that are recorded as a liability at the acquisition date fair value. Subsequent changes in the fair value of the liability are recorded in results of operations. The operating lease liability and finance lease liability represent the undiscounted future lease payments. In the normal course of business, we enter into numerous contractual and commercial undertakings. The following tables should be read in conjunction with our consolidated financial statements. At December 31, 2019, our contractual obligations were (in millions): Obligation Due Total Obligation 2020 2021 - 2022 2023 - 2024 After 2024 Long-term debt: Principal $ 5,122.8 $ 600.0 $ 1,250.0 $ 750.0 $ 2,522.8 Interest 701.6 152.1 240.6 175.6 133.3 Operating lease liability 1,844.1 344.4 523.5 333.7 642.5 Finance lease liability 145.6 49.7 69.0 23.0 3.9 Contingent purchase price obligations 107.7 29.5 54.8 23.4 — Liability for transition tax on accumulated foreign earnings 123.6 11.6 23.1 47.6 41.3 Uncertain tax positions 206.8 43.2 51.4 62.3 49.9 Defined benefit pension plans benefit obligation 293.5 10.4 29.8 40.6 212.7 Postemployment arrangements benefit obligation 146.0 8.7 18.6 17.7 101.0 $ 8,691.7 $ 1,249.6 $ 2,260.8 $ 1,473.9 $ 3,707.4 Commitment Expires Total Commitment 2020 2021 - 2022 2023 - 2024 After 2024 Standby letters of credit $ 4.6 $ 1.0 $ 2.0 $ 0.6 $ 1.0 Guarantees 120.6 55.4 57.1 4.7 3.4 $ 125.2 $ 56.4 $ 59.1 $ 5.3 $ 4.4 26