v3.26.1
Business Combination - Narrative (Details)
$ / shares in Units, $ in Millions
3 Months Ended 6 Months Ended
Jan. 01, 2026
USD ($)
$ / shares
shares
Jun. 30, 2026
USD ($)
$ / shares
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
$ / shares
Jun. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
$ / shares
Business Combination [Line Items]            
Common stock, par value (in dollars per share) | $ / shares   $ 1.00   $ 1.00   $ 1.00
Goodwill $ 1,849 $ 3,479   $ 3,479   $ 1,849
Merger-related expense   51 $ 0 326 $ 0  
Synovus Financial Corp            
Business Combination [Line Items]            
Goodwill 1,630 1,600   $ 1,600    
Purchase accounting adjustment   $ 1        
Identifiable intangible assets 1,110          
Synovus Financial Corp | CDI            
Business Combination [Line Items]            
Identifiable intangible assets $ 848          
Acquired finite-lived intangible assets, useful life 10 years          
Synovus Financial Corp | Wealth Customer Relationships            
Business Combination [Line Items]            
Identifiable intangible assets $ 262          
Acquired finite-lived intangible assets, useful life 14 years          
Synovus Financial Corp            
Business Combination [Line Items]            
Common stock, par value (in dollars per share) | $ / shares $ 1.00          
Synovus Financial Corp | Synovus Financial Corp            
Business Combination [Line Items]            
Conversion ratio (in shares) | shares 0.5237          
Synovus Financial Corp | Synovus Financial Corp | Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, Series D            
Business Combination [Line Items]            
Business combination, conversion ratio (in shares) | shares 1          
Synovus Financial Corp | Synovus Financial Corp | Fixed-Rate Reset Non-Cumulative Perpetual Preferred Stock, Series E            
Business Combination [Line Items]            
Business combination, conversion ratio (in shares) | shares 1          
Legacy Pinnacle            
Business Combination [Line Items]            
Common stock, par value (in dollars per share) | $ / shares $ 1.00          
Conversion ratio (in shares) | shares 1          
Legacy Pinnacle | Fixed-Rate Non-Cumulative Perpetual Preferred Stock, Series C            
Business Combination [Line Items]            
Preferred stock, dividend rate 6.75%          
Legacy Pinnacle | Synovus Financial Corp | Fixed-Rate Non-Cumulative Perpetual Preferred Stock, Series C            
Business Combination [Line Items]            
Business combination, conversion ratio (in shares) | shares 1          
Legacy Pinnacle | Synovus Financial Corp | Preferred Stock            
Business Combination [Line Items]            
Equity interest per share 0.025          
Newco | Fixed-Rate Non-Cumulative Perpetual Preferred Stock, Series C            
Business Combination [Line Items]            
Preferred stock, dividend rate 6.75%