(K) Foreign currency Gains and losses resulting from foreign currency transactions (transactions denominated in a currency other than the entity's functional currency) are reported on the statements of income as other operating costs and expenses. Unrealized gains or losses resulting from translating the results of non-U.S. dollar denominated operations are reported in accumulated other comprehensive income. Revenues and expenses denominated in currencies other than U.S. dollars are generally translated at the weighted average exchange rate during the year. Assets and liabilities are translated at the rate of exchange in effect at the balance sheet date. (L) Property, furniture and equipment Property, furniture and equipment are carried at cost less accumulated depreciation. Depreciation is calculated using the estimated useful lives of the respective assets. Depreciation expense was $54 million, $50 million and $47 million for 2018, 2017 and 2016, respectively. (M) Comprehensive income Comprehensive income encompasses all changes in stockholders' equity (except those arising from transactions with stockholders) and includes net income, net unrealized holding gains or losses on available for sale securities and unrealized foreign currency translation adjustments. (N) Goodwill and other intangible assets Goodwill and other intangible assets are tested for impairment on an annual basis and at interim periods where circumstances require. The Company's impairment test as of December 31, 2018 indicated that there were no material impairment losses related to goodwill and other intangible assets. Intangible assets of $104 million and $107 million are included in other assets as of December 31, 2018 and 2017, respectively. (O) Restricted stock units The costs resulting from all share-based payment transactions with employees are recognized in the consolidated financial statements using a fair-value-based measurement method. Compensation cost is recognized for financial reporting purposes over the period in which the employee is required to provide service in exchange for the award (generally the vesting period). (P) Statements of cash flows Interest payments were $155 million, $145 million and $137 million in 2018, 2017 and 2016, respectively. Income taxes paid were $186 million, $207 million and $232 million in 2018, 2017 and 2016, respectively. Other non-cash items include unrealized investment gains and losses. (See Note 10 of Notes to Consolidated Financial Statements.) (Q) Recent accounting pronouncements Recently adopted accounting pronouncements: In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU 2014-09, Revenue from Customers. ASU 2014-09 clarifies the principles for recognizing revenue. While insurance contracts are not within the scope of this updated guidance, the Company’s insurance service fee revenue and non-insurance business revenue are subject to this updated guidance. The updated guidance requires an entity to recognize revenue as performance obligations are met, in order to reflect the transfer of promised goods or services to customers in an amount that reflects the consideration the entity is entitled to receive for those goods or services. The updated guidance, as amended by ASU 2015-14, was effective for public business entities for annual and interim reporting periods beginning after December 15, 2017. The Company adopted this guidance on January 1, 2018 on a prospective basis. The impact of applying this guidance prospectively was a cumulative effect adjustment that increased retained earnings, a component of stockholders' equity, by $1 million after-tax. 64