v3.26.1
Financial Risks - Summary of Maturity Analysis for Derivative Financial Instruments (Detail) - EUR (€)
€ in Millions
Dec. 31, 2025
Dec. 31, 2024
Disclosure of maturity analysis for derivative financial assets and derivative financial liabilities [line items]    
Gross settled cash inflows € 3,395 € 4,653
Gross settled cash outflows (3,180) (4,345)
Net settled cash inflows 5,881 8,583
Net settled cash outflows (9,224) (13,308)
Not later than 1 year [member]    
Disclosure of maturity analysis for derivative financial assets and derivative financial liabilities [line items]    
Gross settled cash inflows 893 1,301
Gross settled cash outflows (839) (1,241)
Net settled cash inflows 449 582
Net settled cash outflows (436) (475)
Later than one year and not later than two years [member]    
Disclosure of maturity analysis for derivative financial assets and derivative financial liabilities [line items]    
Gross settled cash inflows 192 182
Gross settled cash outflows (176) (135)
Net settled cash inflows 308 425
Net settled cash outflows (280) (360)
Later than two years and not later than three years [member]    
Disclosure of maturity analysis for derivative financial assets and derivative financial liabilities [line items]    
Gross settled cash inflows 141 218
Gross settled cash outflows (126) (191)
Net settled cash inflows 299 380
Net settled cash outflows (237) (323)
Later than three years and not later than four years [member]    
Disclosure of maturity analysis for derivative financial assets and derivative financial liabilities [line items]    
Gross settled cash inflows 175 153
Gross settled cash outflows (182) (134)
Net settled cash inflows 235 323
Net settled cash outflows (221) (259)
Later than four years and not later than five years [member]    
Disclosure of maturity analysis for derivative financial assets and derivative financial liabilities [line items]    
Gross settled cash inflows 128 196
Gross settled cash outflows (116) (194)
Net settled cash inflows 241 286
Net settled cash outflows (223) (246)
Later than 5 years [member]    
Disclosure of maturity analysis for derivative financial assets and derivative financial liabilities [line items]    
Gross settled cash inflows 1,867 2,603
Gross settled cash outflows (1,742) (2,450)
Net settled cash inflows 4,348 6,587
Net settled cash outflows € (7,828) € (11,644)