v3.22.0.1
Borrowings (Narrative) (Details)
$ in Millions
12 Months Ended
Dec. 31, 2021
USD ($)
agreement
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Debt Instrument [Line Items]      
Gain (Loss) on Extinguishment of Debt $ (20) $ (22) $ (16)
Debt, Weighted Average Interest Rate 3.60% 2.70% 3.40%
Proceeds from Issuance of Debt $ 650 $ 750  
Minimum [Member] | Subordinated Debt [Member]      
Debt Instrument [Line Items]      
Debt Instrument, Interest Rate, Stated Percentage 6.45%    
Debt Instrument, Interest Rate, Stated Percentage 6.45%    
Maximum [Member] | Subordinated Debt [Member]      
Debt Instrument [Line Items]      
Debt Instrument, Interest Rate, Stated Percentage 7.75%    
Debt Instrument, Interest Rate, Stated Percentage 7.75%    
Parent Company [Member]      
Debt Instrument [Line Items]      
Gain (Loss) on Extinguishment of Debt $ (20) (14) $ (16)
Parent Company [Member] | Subordinated Debt [Member]      
Debt Instrument [Line Items]      
Number Of Issuances Of Debt | agreement 3    
Subordinated Debt $ 552    
Regions Bank [Member] | Subordinated Debt [Member]      
Debt Instrument [Line Items]      
Number Of Issuances Of Debt | agreement 1    
Subordinated Debt   $ 496