Employee Benefit Plans (Presentation Of The Fair Value Of Regions' Qualified Defined-Benefit Pension Plans' Financial Assets) (Details) - USD ($)	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 1,877,000,000	$ 1,874,000,000	$ 1,936,000,000
Defined Benefit Plan, Common Collective Trust \| Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	102,000,000	117,000,000
Defined Benefit Plan, Common Collective Trust \| Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	114,000,000	126,000,000
Defined Benefit Plan, Common Collective Trust \| International Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	93,000,000	120,000,000
Collective Investment Trust Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	309,000,000	363,000,000
Fair Value Measured at Net Asset Value Per Share \| Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	94,000,000	119,000,000
Fair Value Measured at Net Asset Value Per Share \| Private Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	178,000,000	172,000,000
Estimate of Fair Value [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	1,296,000,000	1,220,000,000
Estimate of Fair Value [Member] \| Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	30,000,000	27,000,000
Estimate of Fair Value [Member] \| Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	1,038,000,000	979,000,000
Estimate of Fair Value [Member] \| Fixed Income Securities [Member] \| US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	508,000,000	362,000,000
Estimate of Fair Value [Member] \| Fixed Income Securities [Member] \| Federal Agency Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	3,000,000	11,000,000
Estimate of Fair Value [Member] \| Fixed Income Securities [Member] \| Corporate Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	527,000,000	606,000,000
Estimate of Fair Value [Member] \| Equity Securities [Member] \| Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	128,000,000	124,000,000
Estimate of Fair Value [Member] \| Mutual Funds [Member] \| International [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	100,000,000	90,000,000
Estimate of Fair Value [Member] \| Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	766,000,000	603,000,000
Estimate of Fair Value [Member] \| Level 1 [Member] \| Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	30,000,000	27,000,000
Estimate of Fair Value [Member] \| Level 1 [Member] \| Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	508,000,000	362,000,000
Estimate of Fair Value [Member] \| Level 1 [Member] \| Fixed Income Securities [Member] \| US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	508,000,000	362,000,000
Estimate of Fair Value [Member] \| Level 1 [Member] \| Fixed Income Securities [Member] \| Federal Agency Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	0	0
Estimate of Fair Value [Member] \| Level 1 [Member] \| Fixed Income Securities [Member] \| Corporate Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	0	0
Estimate of Fair Value [Member] \| Level 1 [Member] \| Equity Securities [Member] \| Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	128,000,000	124,000,000
Estimate of Fair Value [Member] \| Level 1 [Member] \| Mutual Funds [Member] \| International [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	100,000,000	90,000,000
Estimate of Fair Value [Member] \| Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	530,000,000	617,000,000
Estimate of Fair Value [Member] \| Level 2 [Member] \| Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	0	0
Estimate of Fair Value [Member] \| Level 2 [Member] \| Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	530,000,000	617,000,000
Estimate of Fair Value [Member] \| Level 2 [Member] \| Fixed Income Securities [Member] \| US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	0	0
Estimate of Fair Value [Member] \| Level 2 [Member] \| Fixed Income Securities [Member] \| Federal Agency Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	3,000,000	11,000,000
Estimate of Fair Value [Member] \| Level 2 [Member] \| Fixed Income Securities [Member] \| Corporate Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	527,000,000	606,000,000
Estimate of Fair Value [Member] \| Level 2 [Member] \| Equity Securities [Member] \| Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	0	0
Estimate of Fair Value [Member] \| Level 2 [Member] \| Mutual Funds [Member] \| International [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	0	0
Estimate of Fair Value [Member] \| Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	0	0
Estimate of Fair Value [Member] \| Level 3 [Member] \| Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	0	0
Estimate of Fair Value [Member] \| Level 3 [Member] \| Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	0	0
Estimate of Fair Value [Member] \| Level 3 [Member] \| Fixed Income Securities [Member] \| US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	0	0
Estimate of Fair Value [Member] \| Level 3 [Member] \| Fixed Income Securities [Member] \| Federal Agency Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	0	0
Estimate of Fair Value [Member] \| Level 3 [Member] \| Fixed Income Securities [Member] \| Corporate Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	0	0
Estimate of Fair Value [Member] \| Level 3 [Member] \| Equity Securities [Member] \| Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	0	0
Estimate of Fair Value [Member] \| Level 3 [Member] \| Mutual Funds [Member] \| International [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets, Fair Value	$ 0	$ 0

REGIONS FINANCIAL CORP 10-K