Exhibit 12 Computation in Support of Ratio of Earnings to Fixed Charges For Six Months Ended June 30, 2000 (Thousands of Dollars) Earnings: Net income* $157,851 Plus: Fixed charges (see below) 111,398 Income taxes* 96,716 Amortization of capitalized interest 43 Less: Capitalized interest (2,727) Total Earnings $363,281 Fixed Charges: Interest on long-term debt $ 83,002 Other interest 25,215 Estimated interest component of rentals 3,181 Total Fixed Charges $111,398 Ratio of Earnings to Fixed Charges 3.26 *Net income and income taxes excludes extraordinary charges