312 APCo Pension Plans OPEB Years Ended December 31, 2020 2019 2018 2020 2019 2018 (in millions) Service Cost $ 10.5  $ 9.4  $ 9.3  $ 1.0  $ 1.0  $ 1.1  Interest Cost 20.3  25.2  23.5  6.6  8.7  8.2  Expected Return on Plan Assets (33.6) (37.4) (36.6) (14.4) (14.6) (16.0) Amortization of Prior Service Credit —  —  —  (10.2) (10.1) (10.0) Amortization of Net Actuarial Loss 11.2  7.0  10.6  0.9  3.7  1.9  Net Periodic Benefit Cost (Credit) 8.4  4.2  6.8  (16.1) (11.3) (14.8) Capitalized Portion (4.5) (4.0) (3.8) (0.4) (0.4) (0.5) Net Periodic Benefit Cost (Credit) Recognized in Expense $ 3.9  $ 0.2  $ 3.0  $ (16.5) $ (11.7) $ (15.3) I&M Pension Plans OPEB Years Ended December 31, 2020 2019 2018 2020 2019 2018 (in millions) Service Cost $ 15.4  $ 13.4  $ 13.6  $ 1.4  $ 1.4  $ 1.6  Interest Cost 19.7  23.8  22.1  4.7  5.8  5.4  Expected Return on Plan Assets (33.3) (36.8) (35.7) (11.7) (11.4) (12.3) Amortization of Prior Service Credit —  —  —  (9.5) (9.4) (9.5) Amortization of Net Actuarial Loss 10.8  6.6  9.8  0.7  2.7  1.2  Net Periodic Benefit Cost (Credit) 12.6  7.0  9.8  (14.4) (10.9) (13.6) Capitalized Portion (4.3) (3.4) (5.6) (0.4) (0.4) (0.7) Net Periodic Benefit Cost (Credit) Recognized in Expense $ 8.3  $ 3.6  $ 4.2  $ (14.8) $ (11.3) $ (14.3) AEP Texas Pension Plans OPEB Years Ended December 31, 2020 2019 2018 2020 2019 2018 (in millions) Service Cost $ 10.0  $ 8.6  $ 9.2  $ 0.8  $ 0.8  $ 0.9  Interest Cost 13.9  17.5  16.0  3.2  4.0  3.8  Expected Return on Plan Assets (22.7) (25.8) (25.6) (8.0) (7.8) (8.6) Amortization of Prior Service Credit —  —  —  (5.9) (5.9) (5.9) Amortization of Net Actuarial Loss 7.8  4.9  7.2  0.5  1.8  0.8  Net Periodic Benefit Cost (Credit) 9.0  5.2  6.8  (9.4) (7.1) (9.0) Capitalized Portion (5.5) (4.5) (4.8) (0.4) (0.4) (0.5) Net Periodic Benefit Cost (Credit) Recognized in Expense $ 3.5  $ 0.7  $ 2.0  $ (9.8) $ (7.5) $ (9.5)