v3.26.1
Business Combinations - Business Combination (Details) - USD ($)
$ in Millions
Apr. 07, 2026
Jun. 30, 2026
Dec. 31, 2025
Business Combination [Line Items]      
Goodwill   $ 31,866 $ 28,509
Brex Inc.      
Business Combination [Line Items]      
Fair value of cash consideration transferred $ 2,630    
Fair value of purchase consideration 4,521    
Preliminary fair value of assets acquired 2,774    
Preliminary fair value of liabilities assumed 1,322    
Preliminary fair value of net assets acquired 1,452    
Goodwill 3,069    
Recognized long-term debt 815    
Outstanding debt payment 1,100    
Brex Inc. | Credit Card      
Business Combination [Line Items]      
Preliminary fair value of assets acquired 5,800    
Goodwill 3,100 2,400  
Recognized long-term debt 815    
Brex Inc. | Consumer Banking      
Business Combination [Line Items]      
Goodwill   $ 710  
Brex Inc. | Restricted Stock Units      
Business Combination [Line Items]      
Fair value of Capital One stock transferred 13    
Brex Inc. | Technology-Based Intangible Assets      
Business Combination [Line Items]      
Finite lived intangible assets 510    
Brex Inc. | Technology-Based Intangible Assets | Credit Card      
Business Combination [Line Items]      
Finite lived intangible assets 510    
Brex Inc. | Purchased credit card relationships      
Business Combination [Line Items]      
Finite lived intangible assets 432    
Brex Inc. | Purchased credit card relationships | Credit Card      
Business Combination [Line Items]      
Finite lived intangible assets 432    
Brex Inc. | Award      
Business Combination [Line Items]      
Fair value of Capital One stock transferred $ 1,891