v3.22.0.1
Regulatory Capital Requirements and Restrictions (Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations) (Details)
$ in Millions
Dec. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Regions Financial Corporation [Member]    
Basel III Common Equity Tier 1 Capital    
Basel III common equity Tier 1, Amount $ 10,844 $ 10,525
Basel III common equity Tier 1, Ratio 0.0957 [1] 0.0984
Tier One Risk Based Capital    
Tier 1 Capital, Amount $ 12,503 $ 12,181
Tier 1 Capital, Ratio 0.1103 [1] 0.1139
Total Capital    
Total Capital, Amount $ 14,441 $ 14,498
Total Capital, Ratio 0.1274 [1] 0.1356
Leverage Capital    
Leverage, Amount $ 12,503 $ 12,181
Leverage, Ratio 0.0808 [1] 0.0871
Regions Bank [Member]    
Basel III Common Equity Tier 1 Capital    
Basel III common equity Tier 1, Amount $ 12,478 $ 12,972
Basel III common equity Tier 1, Ratio 0.1105 [1] 0.1217
Tier One Risk Based Capital    
Tier 1 Capital, Amount $ 12,478 $ 12,972
Tier 1 Capital, Ratio 0.1105 [1] 0.1217
Total Capital    
Total Capital, Amount $ 13,985 $ 14,803
Total Capital, Ratio 0.1238 [1] 0.1389
Leverage Capital    
Leverage, Amount $ 12,478 $ 12,972
Leverage, Ratio 0.0809 [1] 0.0930
Standardized Approach [Member] | Regions Financial Corporation [Member]    
Basel III Common Equity Tier 1 Capital    
Basel III common equity Tier 1,Minimum Requirement 0.0450 0.0450
Tier One Risk Based Capital    
Tier 1 Capital, Minimum Requirement 0.0600 0.0600
Tier 1 Capital, To Be Well Capitalized 0.0600 0.0600
Total Capital    
Total Capital, Minimum Requirement 0.0800 0.0800
Total Capital, To Be Well Capitalized 0.1000 0.1000
Leverage Capital    
Leverage, Minimum Requirement 0.0400 0.0400
Standardized Approach [Member] | Regions Bank [Member]    
Basel III Common Equity Tier 1 Capital    
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, Minimum Requirement 0.0600 0.0600
Tier 1 Capital, To Be Well Capitalized 0.0800 0.0800
Total Capital    
Total Capital, Minimum Requirement 0.0800 0.0800
Total Capital, To Be Well Capitalized 0.1000 0.1000
Leverage Capital    
Leverage, Minimum Requirement 0.0400 0.0400
Leverage, To Be Well Capitalized 0.0500 0.0500
[1] The 2021 Basel III CET1 capital, Tier 1 capital, Total capital, and Leverage capital ratios are estimated.