ExcessofRedemptionAmountOverCarryingAmount

No definition available.

Name:	rf_ExcessofRedemptionAmountOverCarryingAmount
Namespace Prefix:	rf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

PreferredDividendsReductiontoRetainedEarningsatRedemption

+ References

No definition available.

+ Details

Name:	rf_PreferredDividendsReductiontoRetainedEarningsatRedemption
Namespace Prefix:	rf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

PreferredStockIssuanceCostsReductiontoNetIncome

+ References

No definition available.

+ Details

Name:	rf_PreferredStockIssuanceCostsReductiontoNetIncome
Namespace Prefix:	rf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Stock Repurchased during period related to the Company's deferred investment plan for its directors

+ References

No definition available.

+ Details

Name:	rf_StockRepurchasedDuringPeriodRelatedToTheCompanysDeferredInvestmentPlanForItsDirectors
Namespace Prefix:	rf_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Stockholders' equity and comprehensive income (loss) [Line Items]

+ References

No definition available.

+ Details

Name:	rf_StockholdersEquityAndComprehensiveIncomeLossLineItems
Namespace Prefix:	rf_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

+ Details

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of paid and unpaid preferred stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 405
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6957935&loc=d3e64057-112817

+ Details

Name:	us-gaap_DividendsPreferredStock
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

+ References

+ Details

Name:	us-gaap_PreferredStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The redemption (or callable) amount of currently redeemable preferred stock. Includes amounts representing dividends not currently declared or paid but which will be payable under the redemption features or for which ultimate payment is solely within the control of the issuer.

+ References

+ Details

Name:	us-gaap_PreferredStockRedemptionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Value of all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by shareholders, which is net of related treasury stock. May be all or a portion of the number of preferred shares authorized. These shares represent the ownership interest of the preferred shareholders.

+ References

+ Details

Name:	us-gaap_PreferredStockValueOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

+ Details

Name:	us-gaap_StockRepurchaseProgramAuthorizedAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of shares that have been repurchased and retired during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

+ Details

Name:	us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_StockRepurchasedDuringPeriodValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_StatementClassOfStockAxis=rf_UsGaap_SeriesAandBandCPreferredStockMemberMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesAPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesBPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesCPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesDPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesEPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stockholders' Equity And Accumulated Other Comprehensive Income (Loss) (Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands	3 Months Ended					6 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	May 15, 2029	Sep. 15, 2025	Sep. 15, 2024	Apr. 21, 2021	Dec. 31, 2020
Stockholders' Equity And Comprehensive Income (Loss) [Line Items]
Dividends, Preferred Stock		$ (29,000,000)	$ (28,000,000)	$ (23,000,000)	$ (23,000,000)	$ (57,000,000)
Stock repurchase plan, authorized amount											$ 2,500,000,000
Cash dividend declared (in dollars per share)		$ 0.155		$ 0.155		$ 0.31	$ 0.31
Preferred stock		$ 1,659,000,000				$ 1,659,000,000						$ 1,656,000,000
Preferred Stock, Par Value Per Share (in dollars per share)		$ 1.00				$ 1.00						$ 1.00
Stock Repurchased During Period, Value		$ 167,000,000
Stock Repurchased during period related to the Company's deferred investment plan for its directors		1,000
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased		8,000
us-gaap_SeriesAandBandCPreferredStockMember
Stockholders' Equity And Comprehensive Income (Loss) [Line Items]
Dividends, Preferred Stock						$ (46,000,000)	$ (46,000,000)
Series A Preferred Stock [Member]
Stockholders' Equity And Comprehensive Income (Loss) [Line Items]
PreferredDividendsReductiontoRetainedEarningsatRedemption		$ 100,000,000				100,000,000
PreferredStockIssuanceCostsReductiontoNetIncome		13,000,000				13,000,000
Preferred stock		0				0						$ 387,000,000
Preferred Stock, Redemption Amount		500,000,000				500,000,000
Series B Preferred Stock [Member]
Stockholders' Equity And Comprehensive Income (Loss) [Line Items]
Preferred stock		433,000,000				433,000,000						433,000,000
Series C Preferred Stock [Member]
Stockholders' Equity And Comprehensive Income (Loss) [Line Items]
Preferred stock		490,000,000				490,000,000						490,000,000
Series D Preferred Stock [Member]
Stockholders' Equity And Comprehensive Income (Loss) [Line Items]
Dividends, Preferred Stock						(11,000,000)
Preferred stock		346,000,000				346,000,000						346,000,000
Series E Preferred Stock
Stockholders' Equity And Comprehensive Income (Loss) [Line Items]
Preferred stock		$ 390,000,000				$ 390,000,000						$ 0
Subsequent Event [Member]
Stockholders' Equity And Comprehensive Income (Loss) [Line Items]
Cash dividend declared (in dollars per share)	$ 0.17
Subsequent Event [Member] \| Series B Preferred Stock [Member]
Stockholders' Equity And Comprehensive Income (Loss) [Line Items]
ExcessofRedemptionAmountOverCarryingAmount										$ 67,000,000
PreferredDividendsReductiontoRetainedEarningsatRedemption										$ 52,000,000
Subsequent Event [Member] \| Series C Preferred Stock [Member]
Stockholders' Equity And Comprehensive Income (Loss) [Line Items]
ExcessofRedemptionAmountOverCarryingAmount								$ 10,000,000
Subsequent Event [Member] \| Series D Preferred Stock [Member]
Stockholders' Equity And Comprehensive Income (Loss) [Line Items]
ExcessofRedemptionAmountOverCarryingAmount									$ 4,000,000
Subsequent Event [Member] \| Series E Preferred Stock
Stockholders' Equity And Comprehensive Income (Loss) [Line Items]
ExcessofRedemptionAmountOverCarryingAmount									$ 10,000,000