v3.25.4
Borrowed Funds (Schedule of Long-Term Borrowings) (Details) - USD ($)
$ in Millions
Sep. 06, 2034
Jun. 06, 2029
Dec. 31, 2025
Dec. 31, 2024
Debt Instrument [Line Items]        
Long-term borrowings     $ 4,134 $ 5,993
Parent Company        
Debt Instrument [Line Items]        
Long-term borrowings     2,637 3,495
Parent Company | Senior Notes | Scenario, Forecast        
Debt Instrument [Line Items]        
Long-termdebtfloatingrateinterestequaltoCompoundSOFR (2.06%) (1.49%)    
Parent Company | Valuation Adjustments On Hedged Long Term Debt        
Debt Instrument [Line Items]        
Long-term borrowings     (52) (91)
Parent Company | Two Point Two Five Percent Senior Notes Due April Two Thousand Twenty Five | Senior Notes        
Debt Instrument [Line Items]        
Long-term borrowings     $ 0 749
Stated interest rate     2.25%  
Parent Company | One point Eight Percent Senior Notes Due August Two Thousand Twenty Eight | Senior Notes        
Debt Instrument [Line Items]        
Long-term borrowings     $ 648 647
Stated interest rate     1.80%  
Parent Company | Five point Seven Two Two Percent Senior Note due June Two Thousand Thirty | Senior Notes        
Debt Instrument [Line Items]        
Long-term borrowings     $ 747 746
Stated interest rate     5.722%  
Parent Company | Five point Five Zero Two Percent Senior Note due Septmeber Two Thousand Thirty Five | Senior Notes        
Debt Instrument [Line Items]        
Long-term borrowings     $ 995 994
Stated interest rate     5.502%  
Parent Company | Six Point Seven Five Percent Subordinated Debentures Due November Two Thousand Twenty Five | Subordinated Debt        
Debt Instrument [Line Items]        
Long-term borrowings     $ 0 151
Stated interest rate     6.75%  
Parent Company | Seven Point Three Seven Five Percent Subordinated Notes Due December Two Thousand Thirty Seven | Subordinated Debt        
Debt Instrument [Line Items]        
Long-term borrowings     $ 299 299
Stated interest rate     7.375%  
Regions Bank        
Debt Instrument [Line Items]        
Long-term borrowings     $ 1,497 2,498
Long-Term Federal Home Loan Bank Advances     1,000 2,000
Regions Bank | Other Long Term Debt        
Debt Instrument [Line Items]        
Long-term borrowings     0 2
Regions Bank | Six Point Four Five Percent Subordinated Notes Due June Two Thousand Thirty Seven | Subordinated Debt        
Debt Instrument [Line Items]        
Long-term borrowings     $ 497 $ 496
Stated interest rate     6.45%