Other intangible assets Current assets Other intangible assets Current assets Payments relating to exceptional charges in operating costs Payments relating to exceptional charges in operating costs Current liabilities Disclosure of Merger, capital redemption and other reserves [Text Block] Disclosure of Merger, capital redemption and other reserves Disclosure of basis of restatement [Text Block] Disclosure of basis of restatement Group revenue Group revenue Unrealised (gains)/losses arising from re-measurement of energy contracts Unrealised (gains)/losses arising from re-measurement of energy contracts Non-current liabilities Re-measurement and settlement of derivative energy contracts Re-measurement and settlement of derivative energy contracts Current provisions Credit losses on financial assets Credit losses on financial assets Non-current provisions Exchange differences reclassified to the Group Income Statement on disposal Exchange differences reclassified to the Group Income Statement on disposal Insurance services operating costs Insurance services operating costs Non current Securities Non current Securities Share buyback programme Share buyback programme Non-current portion of non-current borrowings Accounting policy for Cloud Computing arrangements [Text Block] Accounting policy for Cloud Computing arrangements Trade and other current payables Operating cash flows before payments relating to taxes, exceptional charges and operating interest Operating cash flows before payments relating to taxes, exceptional charges and operating interest Non-current net defined benefit liability Insurance contracts that are liabilities Exchange Differences On Translation Of Foreign Operations Attributable To Non Controlling Interests Exchange Differences On Translation Of Foreign Operations Attributable To Non Controlling Interests Exchange Differences On Translation Of Foreign Operations Attributable To Non Controlling Interests Investments in joint ventures and associates classified as investing activities Investments in joint ventures and associates classified as investing activities Business Performance [Member] Business Performance climate change [Text Block] climate change Trade and other non-current payables Liabilities included in disposal groups classified as held for sale Deferred tax liabilities Interim dividend paid per ordinary share Interim dividend paid per ordinary share Group Income Statement [Axis] Group Income Statement Share buyback programme classified as financing activities Share buyback programme classified as financing activities Share buyback programme classified as financing activities Exceptional items Exceptional items Sources of Finance [Text Block] Sources of Finance Accounting policy for re-measurement and settlement of energy contracts [Text Block] Accounting policy for re-measurement and settlement of energy contracts Repayments of borrowings, classified as financing activities Accounting Policy for Renewable certificates [Text Block] Accounting Policy for Renewable certificates cost of sales Onerous energy supply contract provision cost of sales Onerous energy supply contract provision Disclosure of Exceptional Items and Certain Re-measurements [Text Block] Disclosure of Exceptional Items and Certain Re-measurements Description of accounting policy for exceptional items and re-measurements [Text Block] Description of accounting policy for exceptional items and re-measurements Operating expense Non-current derivative financial liabilities Current Securities Current Securities Description of accounting policy for use of adjusted performance measures [Text Block] Description of accounting policy for use of adjusted performance measures Results for the year [Member] Results for the year Cash flows used in obtaining control of subsidiaries or other businesses, classified as investing activities Insurance services cost of sales Insurance services cost of sales Current tax liabilities Description of accounting policy for Nuclear activity [Text Block] Description of accounting policy for Nuclear activity Adjustments for (gain)/loss on disposals Adjustments for (gain)/loss on disposals Group operating profit before share of results of joint ventures and associates Group operating profit before share of results of joint ventures and associates Group Income Statement [Member] Group Income Statement Accounting Policy for UK and EU emissions trading scheme [Text Block] Accounting Policy for UK and EU emissions trading scheme Description of Accounting policy for Securities [Text Block] Description of Accounting policy for Securities Purchase of property, plant and equipment, classified as investing activities Accounting policy for cost of sales [Text Block] Accounting policy for cost of sales Operating costs before insurance services operating costs, exceptional items and credit losses on financial assets Operating costs before insurance services operating costs, exceptional items and credit losses on financial assets Exchange Differences On Translation Of Foreign Operations Attributable To Equity Holders Of Parent Exchange Differences On Translation Of Foreign Operations Attributable To Equity Holders Of Parent Other cash payments to acquire equity or debt instruments of other entities, classified as investing activities Current borrowings and current portion of non-current borrowings Dividends paid to equity holders of parent, classified as financing activities Results relating to joint ventures and associates, net of interest and taxation Results relating to joint ventures and associates, net of interest and taxation Exceptional items and certain re-measurements [Member] Exceptional items and certain re-measurements Interest paid, classified as financing activities Purchase of interests in investments accounted for using equity method Current derivative financial liabilities Description of accounting policy for Other investments [Text Block] Description of accounting policy for Other investments