v3.26.1
Issued capital (Details) - EUR (€)
12 Months Ended
Dec. 23, 2025
Jun. 03, 2025
Dec. 20, 2024
Jul. 01, 2024
Feb. 05, 2024
Jun. 30, 2023
Mar. 21, 2023
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Disclosure of classes of share capital [line items]                      
Capital stock               € 7,345,000,000 € 7,576,000,000 € 8,092,000,000 € 8,397,000,000
Share capital (in shares)               14,689,319,502 15,152,492,322 16,184,146,059 16,794,401,584
Nominal value per share (in euro per share)               € 0.50 € 0.50 € 0.50 € 0.50
Reduction of issued capital               € 8,000,000 € 93,000,000 € 0  
Purchase of treasury shares (in shares)               584,363,745 930,610,636    
Crest depositary interest, share equivalent (in shares)               1      
American depositary receipt, share equivalent (in shares)               1      
Percentage of equity interests held by significant shareholders, minimum threshold               3.00%      
Percentage of equity interests held by a single shareholder residing in tax haven, minimum threshold               1.00%      
Number of shares owned by third parties managed by Group management companies (in shares)               33,000,000 40,000,000 36,000,000  
Shares owned by third parties managed by Group management companies, percentage of share capital               0.22% 0.26% 0.22%  
Shares owned by third parties and received as security (in shares)               28,000,000      
Shares owned by third parties received as security, percentage of share capital               0.19%      
2023 Program                      
Disclosure of classes of share capital [line items]                      
Purchase of treasury shares (in shares)                   286,842,316  
State Street Bank                      
Disclosure of classes of share capital [line items]                      
Percentage of equity interests held by significant shareholders               13.90%      
Chase Nominees Limited                      
Disclosure of classes of share capital [line items]                      
Percentage of equity interests held by significant shareholders               7.50%      
Bank of New York Mellon Corporation                      
Disclosure of classes of share capital [line items]                      
Percentage of equity interests held by significant shareholders               7.18%      
Citibank                      
Disclosure of classes of share capital [line items]                      
Percentage of equity interests held by significant shareholders               6.40%      
BNP Paribas                      
Disclosure of classes of share capital [line items]                      
Percentage of equity interests held by significant shareholders               3.74%      
Caceis Bank                      
Disclosure of classes of share capital [line items]                      
Percentage of equity interests held by significant shareholders               3.57%      
The Northern Trust                      
Disclosure of classes of share capital [line items]                      
Percentage of equity interests held by significant shareholders               3.06%      
(-) Own shares                      
Disclosure of classes of share capital [line items]                      
Share capital (in shares)               11,077,291 15,529,459 297,815,673  
Reduction of issued capital € 98,002,935 € 133,583,475 € 170,890,625 € 165,652,500 € 179,283,743.5 € 134,924,476.5 € 170,203,286 € (3,287,000,000) € (4,294,000,000) € (1,900,000,000)  
Redemption of treasury shares, shares 196,005,870 267,166,950 341,781,250 331,305,000 358,567,487 269,848,953 340,406,572