LEASES - Schedule of Maturities of Lease Liabilities (Details) $ in Millions	May 30, 2021 USD ($)
Leases [Abstract]
Operating Leases, 2022	$ 46.5
Operating Leases, 2023	41.2
Operating Leases, 2024	32.4
Operating Leases, 2025	24.4
Operating Leases, 2026	20.9
Operating Leases, Later years	102.8
Operating Leases, Total lease payments	268.2
Less: Operating Leases, Imputed interest	(43.3)
Operating Leases, Total lease liabilities	$ 224.9
Operating Lease, Liability, Statement of Financial Position [Extensible List]	cag:OtherAccruedLiabilitiesAndOtherNoncurrentLiabilitiesMember
Finance Leases, 2022	$ 28.5
Finance Leases, 2023	25.3
Finance Leases, 2024	20.4
Finance Leases, 2025	18.3
Finance Leases, 2026	15.0
Finance Leases, Later years	63.9
Finance Leases, Total lease payments	171.4
Less: Finance Leases, Imputed interest	(32.3)
Finance Leases, Total lease liabilities	139.1
2022	75.0
2023	66.5
2024	52.8
2025	42.7
2026	35.9
Later years	166.7
Total lease payments	439.6
Less: Imputed interest	(75.6)
Total lease liabilities	$ 364.0

Lessee, operating and finance lease liability payments due.

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- Definition

Lessee, operating and finance lease liability payments due after year five.

+ References

No definition available.

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- Definition

Lessee operating and finance lease liability payments due next twelve months.

+ References

No definition available.

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- Definition

Lessee, operating and finance lease liability payments due year five.

+ References

No definition available.

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- Definition

Lessee, operating and finance lease liability payments due year four.

+ References

No definition available.

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- Definition

Lessee, operating and finance lease liability payments due year three.

+ References

No definition available.

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- Definition

Lessee, operating and finance lease liability payments due year two.

+ References

No definition available.

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- Definition

Lessee, operating and finance lease liability undiscounted excess amount.

+ References

No definition available.

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- Definition

Operating and finance lease liability.

+ References

No definition available.

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Name:	cag_OperatingAndFinanceLeaseLiability
Namespace Prefix:	cag_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Present value of lessee's discounted obligation for lease payments from finance lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918701-209980

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of lessee's undiscounted obligation for lease payments for finance lease.

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid 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

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in next 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

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid 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

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid 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

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid 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

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid 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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- Definition

Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for finance lease.

+ References

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- References

No definition available.

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease.

+ References

+ Details

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

- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease due 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 lessee's undiscounted obligation for lease payment for operating lease to be paid in next 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

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid 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

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid 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

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid 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

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid 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

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- Definition

Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease.

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- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977

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- Definition

Indicates line item in statement of financial position that includes operating lease liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918631-209977

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