Exhibit (12) Commonwealth Edison Company Form 10-Q File No. 1-1839 Commonwealth Edison Company and Subsidiary Companies Consolidated ----------------------------------------------------------------- Computation of Ratios of Earnings to Fixed Charges and Ratios of Earnings to Fixed Charges and Preferred and Preference Stock Dividend Requirements ---------------------------------------------------- (Thousands of Dollars) Twelve Months Ended -------------------------------- Line September 30, December 31, No. 1998 1997 - ---- ----------- ------------- 1 Net income (loss) before extraordinary item and cumulative effect of 2 change in accounting principle $ (65,071) $(160,138) --------- --------- 3 Net provisions for income taxes and investment tax credits deferred 4 charged to- 5 Operations $ 327,975 $ 307,276 6 Other income (405,764) (405,819) --------- --------- 7 $ (77,789) $ (98,543) --------- --------- 8 Fixed charges- 9 Interest on debt $ 457,065 $ 487,749 10 Estimated interest component of nuclear fuel and other lease payments, rentals and other interest 75,707 70,468 12 Amortization of debt discount, premium and expense 12,789 21,951 13 Company-obligated mandatorily redeemable preferred securities 14 dividend requirements of subsidiary trusts holding solely the 15 Company's subordinated debt securities 29,710 28,860 --------- --------- 16 $ 575,271 $ 609,028 --------- --------- 17 Preferred and preference stock dividend requirements- 18 Provisions for preferred and preference stock dividends $ 57,635 $ 60,486 19 Taxes on income required to meet provisions for 20 preferred and preference stock dividends 37,744 39,623 --------- --------- 21 $ 95,379 $ 100,109 --------- --------- 22 Fixed charges and preferred and preference stock 23 dividend requirements $ 670,650 $ 709,137 --------- --------- 24 Earned for fixed charges and preferred and preference stock 25 dividend requirements $ 432,411 $ 350,347 --------- --------- 26 Ratios of earnings to fixed charges (line 25 divided by line 16) 0.75 0.58 ==== ==== 27 Ratios of earnings to fixed charges and preferred and preference 28 stock dividend requirements (line 25 divided by line 25 divided by line 23) 0.64 0.49 ==== ====