v3.20.4
Regulatory Capital Requirements and Restrictions (Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations) (Details) - Standardized Approach [Member]
$ in Millions
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Regions Financial Corporation [Member]    
Basel III Common Equity Tier 1 Capital    
Basel III common equity Tier 1, Amount $ 10,525 $ 10,228
Basel III common equity Tier 1, Ratio 0.0984 [1] 0.0968
Basel III common equity Tier 1,Minimum Requirement 0.0450 0.0450
Tier One Risk Based Capital    
Tier 1 Capital, Amount $ 12,181 $ 11,537
Tier 1 Capital, Ratio 0.1139 [1] 0.1091
Tier 1 Capital, Minimum Requirement 0.0600 0.0600
Tier 1 Capital, To Be Well Capitalized 0.0600 0.0600
Total Capital    
Total Capital, Amount $ 14,498 $ 13,406
Total Capital, Ratio 0.1356 [1] 0.1268
Total Capital, Minimum Requirement 0.0800 0.0800
Total Capital, To Be Well Capitalized 0.1000 0.1000
Leverage Capital    
Leverage, Amount $ 12,181 $ 11,537
Leverage, Ratio 0.0871 [1] 0.0965
Leverage, Minimum Requirement 0.0400 0.0400
Regions Bank [Member]    
Basel III Common Equity Tier 1 Capital    
Basel III common equity Tier 1, Amount $ 12,972 $ 12,212
Basel III common equity Tier 1, Ratio 0.1217 [1] 0.1158
Basel III common equity Tier 1,Minimum Requirement 0.0450 0.0450
Basel III common equity Tier 1, To Be Well Capitalized 0.0650 0.0650
Tier One Risk Based Capital    
Tier 1 Capital, Amount $ 12,972 $ 12,212
Tier 1 Capital, Ratio 0.1217 [1] 0.1158
Tier 1 Capital, Minimum Requirement 0.0600 0.0600
Tier 1 Capital, To Be Well Capitalized 0.0800 0.0800
Total Capital    
Total Capital, Amount $ 14,803 $ 13,621
Total Capital, Ratio 0.1389 [1] 0.1292
Total Capital, Minimum Requirement 0.0800 0.0800
Total Capital, To Be Well Capitalized 0.1000 0.1000
Leverage Capital    
Leverage, Amount $ 12,972 $ 12,212
Leverage, Ratio 0.0930 [1] 0.1024
Leverage, Minimum Requirement 0.0400 0.0400
Leverage, To Be Well Capitalized 0.0500 0.0500
[1] The 2020 Basel III CET1 capital, Tier 1 capital, Total capital, and Leverage capital ratios are estimated.