Leases (Lessor: Schedule of Minimum Future Payments Due From Customers for Sales-Type, Direct Financing, and Operating Leases) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Remainder of Fiscal Year	$ 297
Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Two Years	236
Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Three Years	178
Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Four Years	118
Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Five Years	76
Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Thereafter	388
Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received	1,293
Lessor, Operating Lease, Payments to be Received, Remainder of Fiscal Year	24
Lessor, Operating Lease, Payments to be Received, Two Years	14
Lessor, Operating Lease, Payments to be Received, Three Years	7
Lessor, Operating Lease, Payments to be Received, Four Years	6
Lessor, Operating Lease, Payments to be Received, Five Years	3
Lessor, Operating Lease, Payments to be Received, Thereafter	6
Lessor, Operating Lease, Payments to be Received	60	$ 113
Lessor, Sales-type, Direct Financing and Operating Leases, Payments to be Received, Remainder of Fiscal Year	321
Lessor, Sales-type, Direct Financing and Operating Leases, Payments to be Received, Two Years	250
Lessor, Sales-type, Direct Financing and Operating Leases, Payments to be Received, Three Years	185
Lessor, Sales-type, Direct Financing and Operating Leases, Payments to be Received, Four Years	124
Lessor, Sales-type, Direct Financing and Operating Leases, Payments to be Received, Five Years	79
Lessor, Sales-type, Direct Financing and Operating Leases, Payments to be Received, Thereafter	394
Lessor, Sales-type, Direct Financing and Operating Leases, Payments to be Received	$ 1,353

Lessor, Sales-type, Direct Financing and Operating Leases, Payments to be Received

No definition available.

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Period Type:	instant

- Definition

Lessor, Sales-type, Direct Financing and Operating Leases, Payments to be Received, Five Years

+ References

No definition available.

+ Details

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- Definition

Lessor, Sales-type, Direct Financing and Operating Leases, Payments to be Received, Four Years

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Lessor, Sales-type, Direct Financing and Operating Leases, Payments to be Received, Next twelve months

+ References

No definition available.

+ Details

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Balance Type:	debit
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- Definition

Lessor, Sales-type, Direct Financing and Operating Leases, Payments to be Received, Thereafter

+ References

No definition available.

+ Details

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- Definition

Lessor, Sales-type, Direct Financing and Operating Leases, Payments to be Received, Three Years

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

Lessor, Sales-type, Direct Financing and Operating Leases, Payments to be Received, Two Years

+ References

No definition available.

+ Details

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Namespace Prefix:	rf_
Data Type:	xbrli:monetaryItemType
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- References

No definition available.

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- Definition

Amount of lease payments to be received by lessor for operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=121576215&loc=SL77919396-209981

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease payment to be received by lessor for operating lease in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

Amount of lease payment to be received by lessor for operating lease in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lease payments to be received by lessor in next rolling twelve months following latest statement of financial position date for operating lease. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=121576215&loc=SL77919396-209981

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease payment to be received by lessor for operating lease after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lease payment to be received by lessor for operating lease in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lease payment to be received by lessor for operating lease in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121576215&loc=SL77919391-209981

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in next rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121576215&loc=SL77919391-209981

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Balance Type:	debit
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- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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Balance Type:	debit
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- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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