GENERATION & MARKETING (a) Other AEP Segments excludes Corporate and Other which is not considered a reportable segment. 96 Years Ended December 31, Generation & Marketing 2020 2019 2018 (in millions) Revenues $ 1,725.6  $ 1,857.6  $ 1,940.3  Fuel, Purchased Electricity and Other 1,403.6  1,456.2  1,537.3  Gross Margin 322.0  401.4  403.0  Other Operation and Maintenance 124.9  223.8  229.3  Asset Impairments and Other Related Charges —  31.0  47.7  Depreciation and Amortization 72.8  69.5  41.0  Taxes Other Than Income Taxes 13.2  15.6  13.4  Operating Income 111.1  61.5  71.6  Interest and Investment Income 3.2  7.7  13.1  Non-Service Cost Components of Net Periodic Benefit Cost 15.4  14.9  15.2  Interest Expense (24.0) (30.0) (14.9) Income Before Income Tax Benefit and Equity Earnings (Loss) 105.7  54.1  85.0  Income Tax Benefit (108.0) (53.8) (49.2) Equity Earnings (Loss) of Unconsolidated Subsidiaries 3.2  (3.8) 0.5  Net Income 216.9  104.1  134.7  Net Loss Attributable to Noncontrolling Interests (10.0) (8.7) (0.6) Earnings Attributable to AEP Common Shareholders $ 226.9  $ 112.8  $ 135.3 