Comprehensive Income Attributable To Equity Shareholders Of The Parent From Discontinued Operations Comprehensive Income Attributable To Equity Shareholders Of The Parent From Discontinued Operations Comprehensive Income For The Year From Continuing Operations Comprehensive Income For The Year From Continuing Operations Comprehensive Income For The Year From Continuing Operations Before Exceptional Items And Remeasurements, Netting [Member] Before Exceptional Items And Remeasurements, Netting Transfer Of Accumulated Gains And Losses On Sale Of Equity Investments Transfer Of Accumulated Gains And Losses On Sale Of Equity Investments Description Of Accounting Policy For Sensitivities Description Of Accounting Policy For Sensitivities Cash flows from (used in) investing activities, continuing operations Exceptional Items And Remeasurements, Netting [Member] Exceptional Items And Remeasurements, Netting Consolidated Income Statement [Member] Consolidated Income Statement Transactions In Own Shares Transactions In Own Shares Disclosure Of Consolidated Income Statement [Table] Disclosure Of Consolidated Income Statement Consolidated Income Statement [Axis] Consolidated Income Statement Cash flows from (used in) financing activities, continuing operations Disposal Of Interest In St William Homes LLP Classified As Investing Activities Disposal Of Interest In St William Homes LLP Classified As Investing Activities Cash flows from (used in) operating activities, continuing operations Other Comprehensive Income/(Loss) For The Year, Net Of Tax, From Continuing Operations Other Comprehensive Income/(Loss) For The Year, Net Of Tax, From Continuing Operations Other Comprehensive Income/(Loss) For The Year, Net Of Tax, From Continuing Operations Disclosure Of Exceptional Items And Remeasurements [Text Block] Disclosure Of Exceptional Items And Remeasurements Cash Outflows On Derivatives Classified As Financing Activities Cash Outflows On Derivatives Classified As Financing Activities Description Of Accounting Policy For Contract Liabilities Description Of Accounting Policy For Contract Liabilities Cash Inflows On Derivatives Classified As Financing Activities Cash Inflows On Derivatives Classified As Financing Activities Net Movements In Short-Term Financial Investments Classified As Investing Activities Net Movements In Short-Term Financial Investments Classified As Investing Activities Scrip Dividend-Related Share Issue Scrip Dividend-Related Share Issue Disclosure Of Sensitivities [Text Block] Disclosure Of Sensitivities Cash Flow Hedges Transferred To The Statement Of Financial Position, Net Of Tax Cash Flow Hedges Transferred To The Statement Of Financial Position, Net Of Tax Cash Flows Relating To Exceptional Items Classified As Investing Activities Cash Flows Relating To Exceptional Items Classified As Investing Activities Increase (Decrease) In Cash And Cash Equivalents Through Reclassification To Held For Sale And Discontinued Operations Increase (Decrease) In Cash And Cash Equivalents Through Reclassification To Held For Sale And Discontinued Operations Adjustments For Exceptional Items And Remeasurements Adjustments For Exceptional Items And Remeasurements Description Of Accounting Policy For Impact Of Climate Change And The Transition Of Net Zero [Text Block] Description Of Accounting Policy For Impact Of Climate Change And The Transition Of Net Zero Disposal Of Interest In The UK Gas Transmission Business Classified As Investing Activities Disposal Of Interest In The UK Gas Transmission Business Classified As Investing Activities Other Comprehensive Income/(Loss) For The Year, Net Of Tax, From Discontinued Operations Other Comprehensive Income/(Loss) For The Year, Net Of Tax, From Discontinued Operations Adjustments For Cash Flows Relating To Exceptional Items Adjustments For Cash Flows Relating To Exceptional Items Disclosure Of Contract Liabilities [Text Block] Disclosure Of Contract Liabilities Cash and cash equivalents if different from statement of financial position Cash and cash equivalents if different from statement of financial position Property Plant And Equipment Including Right Of Use Assets Property Plant And Equipment Including Right Of Use Assets Comprehensive Income Attributable To Equity Shareholders Of The Parent From Continuing Operations Comprehensive Income Attributable To Equity Shareholders Of The Parent From Continuing Operations Description Of Accounting Policy For Other Non-Current Liabilities Description Of Accounting Policy For Other Non-Current Liabilities Net Losses In Respect Of Cash Flow Hedging Of Capital Expenditure Net Losses In Respect Of Cash Flow Hedging Of Capital Expenditure Disposal Of Interest In Millennium Pipeline Company LLC Classified As Investing Activities Disposal Of Interest In Millennium Pipeline Company LLC Classified As Investing Activities Consolidated Income Statement [Line Items] Consolidated Income Statement Accumulated Losses Transferred To Retained Earnings On Disposal Accumulated Losses Transferred To Retained Earnings On Disposal Comprehensive Income For The Year From Discontinued Operations Comprehensive Income For The Year From Discontinued Operations Comprehensive Income For The Year From Discontinued Operations Net Gains/(Losses) In Respect Of Cost Of Hedging Net Gains/(Losses) In Respect Of Cost Of Hedging Description Of Accounting Policy For Other Non-Current Assets Description Of Accounting Policy For Other Non-Current Assets Cash flows from (used in) operations Assets (liabilities) Increase (decrease) in cash and cash equivalents before effect of exchange rate changes Disposal Of Interest In The Narragansett Electric Company Classified As Investing Activities Disposal Of Interest In The Narragansett Electric Company Classified As Investing Activities