v3.19.3.a.u2
Regulatory Capital Requirements and Restrictions (Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations) (Details) - Standardized Approach [Member] - Transitional Basis Basel III Regulatory Capital Rules [Member] - USD ($)
$ in Millions
Dec. 31, 2019
Dec. 31, 2018
Regions Financial Corporation [Member]    
Basel III Common Equity Tier 1 Capital    
Basel III common equity Tier 1, Amount $ 10,228 [1] $ 10,371
Basel III common equity Tier 1, Ratio 9.68% [1] 9.90%
Basel III common equity Tier 1,Minimum Requirement 4.50% 4.50%
Tier One Risk Based Capital    
Tier 1 Capital, Amount $ 11,537 [1] $ 11,190
Tier 1 Capital, Ratio 10.91% [1] 10.68%
Tier 1 Capital, Minimum Requirement 6.00% 6.00%
Tier 1 Capital, To Be Well Capitalized 6.00% 6.00%
Total Capital    
Total Capital, Amount $ 13,406 [1] $ 13,056
Total Capital, Ratio 12.68% [1] 12.46%
Total Capital, Minimum Requirement 8.00% 8.00%
Total Capital, To Be Well Capitalized 10.00% 10.00%
Leverage Capital    
Leverage, Amount $ 11,537 [1] $ 11,190
Leverage, Ratio 9.65% [1] 9.32%
Leverage, Minimum Requirement 4.00% 4.00%
Regions Bank [Member]    
Basel III Common Equity Tier 1 Capital    
Basel III common equity Tier 1, Amount $ 12,212 [1] $ 12,109
Basel III common equity Tier 1, Ratio 11.58% [1] 11.59%
Basel III common equity Tier 1,Minimum Requirement 4.50% 4.50%
Basel III common equity Tier 1, To Be Well Capitalized 6.50% 6.50%
Tier One Risk Based Capital    
Tier 1 Capital, Amount $ 12,212 [1] $ 12,109
Tier 1 Capital, Ratio 11.58% [1] 11.59%
Tier 1 Capital, Minimum Requirement 6.00% 6.00%
Tier 1 Capital, To Be Well Capitalized 8.00% 8.00%
Total Capital    
Total Capital, Amount $ 13,621 [1] $ 13,494
Total Capital, Ratio 12.92% [1] 12.92%
Total Capital, Minimum Requirement 8.00% 8.00%
Total Capital, To Be Well Capitalized 10.00% 10.00%
Leverage Capital    
Leverage, Amount $ 12,212 [1] $ 12,109
Leverage, Ratio 10.24% [1] 10.12%
Leverage, Minimum Requirement 4.00% 4.00%
Leverage, To Be Well Capitalized 5.00% 5.00%
[1] The 2019 Basel III CET1 capital, Tier 1 capital, Total capital, and Leverage capital ratios are estimated.