82 Consolidated  Notes to the  Financial  Statements Note 4 – Segment information (continued) Retail Energy  $m Merchant  Energy  $m Upstream Gas  $m Energy  Investments  $m Other  $m Total  $m 2012 Revenue Total segment revenue 4,194.3  4,955.7  80.1  –  0.1  9,230.2  Inter-segment revenue –  (1,743.1) (31.5) –  –  (1,774.6) External revenue 4,194.3  3,212.6  48.6  –  0.1  7,455.6  Earnings before interest, tax, depreciation and amortisation  (EBITDA) 391.9  628.5  20.6  24.5  (161.2) 904.3  Depreciation and amortisation (59.1) (78.8) (20.0) –  (16.0) (173.9) Operating EBIT 332.8  549.7  0.6  24.5  (177.2) 730.4  Net financing costs (51.2) Underlying profit before income tax 679.2  Income tax expense (197.2) Underlying profit 482.0  Segment assets 3,455.0  6,656.8  1,360.4  116.9  116.1  11,705.2  Segment liabilities 424.1  1,392.9  101.9  –  136.5  2,055.4  Other segment information Share of profits of associates and jointly controlled entities –  –  (0.1) 16.9  –  16.8  Investments in associates and jointly controlled entities –  –  4.4  27.2  –  31.6  Additions to non-current assets 110.7  3,020.4  147.2  1.6  30.8  3,310.7  Other non-cash expenses (61.7) (5.2) –  –  (6.4) (73.3) (Loss)/gain in fair value of financial instruments –  (308.6) –  4.0  –  (304.6) Significant expense items –  (15.9) (35.8) (157.0) (3.0) (211.7) 2011 Revenue Total segment revenue 3,662.7  4,988.4  80.7  –  –  8,731.8  Inter-segment revenue –  (1,627.8) (31.5) –  –  (1,659.3) External revenue 3,662.7  3,360.6  49.2  –  –  7,072.5  Earnings before interest, tax, depreciation and amortisation  (EBITDA) 348.9  522.3  35.8  40.5  (143.0) 804.5  Depreciation and amortisation (43.8) (69.1) (21.5) –  (13.6) (148.0) Operating EBIT 305.1  453.2  14.3  40.5  (156.6) 656.5  Net financing costs (37.4) Underlying profit before income tax 619.1  Income tax expense (188.0) Underlying profit 431.1  Segment assets 3,219.7  3,704.6  1,278.9  351.0  91.8  8,646.0  Segment liabilities 213.7  773.1  83.8  –  107.7  1,178.3  Other segment information Share of profits of associates and jointly controlled entities –  –  0.5  33.1  –  33.6  Investments in associates and jointly controlled entities –  –  4.4  236.3  –  240.7  Additions to non-current assets 81.1  317.3  277.5  –  27.9  703.8  Impairment losses –  –  (0.2) –  –  (0.2) Other non-cash expenses (58.4) (4.2) –  –  (2.0) (64.6) Gain in fair value of financial instruments –  213.0  –  5.8  –  218.8  Significant expense items (4.1) (6.1) –  –  (34.1) (44.3)