v3.22.0.1
Borrowings (Schedule of Long-Term Borrowings) (Details) - USD ($)
$ in Millions
Dec. 31, 2021
Dec. 31, 2020
Debt Instrument [Line Items]    
Long-term borrowings $ 2,407 $ 3,569
Parent Company [Member]    
Debt Instrument [Line Items]    
Long-term borrowings 1,909 2,718
Parent Company [Member] | Senior Notes [Member] | Three Point Two Zero Percent Senior Notes Due February 2021 [Member]    
Debt Instrument [Line Items]    
Long-term borrowings 0 360
Parent Company [Member] | Senior Notes [Member] | Three Point Eight Zero Percent Senior Notes Due August 2023 [Member] [Member]    
Debt Instrument [Line Items]    
Long-term borrowings 0 997
Parent Company [Member] | Senior Notes [Member] | Two Point Two Five Percent Senior Notes Due April Two Thousand Twenty Five [Member]    
Debt Instrument [Line Items]    
Long-term borrowings 746 744
Parent Company [Member] | Senior Notes [Member] | One point Eight Percent Senior Notes Due August Two Thousand    
Debt Instrument [Line Items]    
Long-term borrowings 645 0
Parent Company [Member] | Subordinated Debt [Member] | Seven Point Seven Five Percent Subordinated Notes Due September Two Thousand Twenty Four [Member]    
Debt Instrument [Line Items]    
Long-term borrowings 100 100
Parent Company [Member] | Subordinated Debt [Member] | Six Point Seven Five Percent Subordinated Debentures Due November Two Thousand Twenty Five [Member]    
Debt Instrument [Line Items]    
Long-term borrowings 154 155
Parent Company [Member] | Subordinated Debt [Member] | Seven Point Three Seven Five Percent Subordinated Notes Due December Two Thousand Thirty Seven [Member]    
Debt Instrument [Line Items]    
Long-term borrowings 298 298
Parent Company [Member] | Valuation Adjustments On Hedged Long Term Debt [Member]    
Debt Instrument [Line Items]    
Long-term borrowings (34) 64
Regions Bank [Member]    
Debt Instrument [Line Items]    
Long-term borrowings 498 851
Regions Bank [Member] | Senior Notes [Member] | Two Point Seven Five Percent Senior Notes Due April Two Thousand Twenty-One [Member]    
Debt Instrument [Line Items]    
Long-term borrowings 0 190
Regions Bank [Member] | Senior Notes [Member] | Three Month LIBOR Plus Point Three Eight Percent of Floating Rate Senior Notes due April 2021 [Member]    
Debt Instrument [Line Items]    
Long-term borrowings 0 66
Regions Bank [Member] | Subordinated Debt [Member] | Six Point Four Five Percent Subordinated Notes Due June Two Thousand Thirty Seven [Member]    
Debt Instrument [Line Items]    
Long-term borrowings 496 496
Regions Bank [Member] | Subordinated Debt [Member] | Ascentium Note Securitizations[Member]    
Debt Instrument [Line Items]    
Long-term borrowings 0 97
Regions Bank [Member] | Other Long Term Debt [Member]    
Debt Instrument [Line Items]    
Long-term borrowings $ 2 $ 2