Weighted Average Assumptions Used for Pension Plans (Detail)	12 Months Ended
Dec. 31, 2022	Jan. 01, 2022	Jan. 02, 2021
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Weighted average assumptions used to determine Measurement date	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Weighted average assumptions used to determine benefit obligations, Discount rate	3.06%	2.78%	2.54%
Weighted average assumptions used to determine benefit obligations, Rate of compensation increase	3.00%	3.00%	3.00%
Weighted average assumptions used to determine Measurement date	Jan. 01, 2022	Jan. 01, 2021	Jan. 01, 2020
Weighted average assumptions used to determine net periodic benefit cost/(income), Discount rate	5.65%	3.06%	2.78%
Weighted average assumptions used to determine net periodic benefit cost/(income), Expected return on plan assets	5.90%	5.70%	4.97%
Weighted average assumptions used to determine net periodic benefit cost/(income), Rate of compensation increase	3.00%	3.00%	3.00%
Postretirement Benefit Plans \| Benefit Obligations
Defined Benefit Plan Disclosure [Line Items]
Weighted average assumptions used to determine Measurement date	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Weighted average assumptions used to determine benefit obligations, Discount rate	2.60%	2.11%	3.01%
Health care cost trend rate, Initial rate	6.25%	6.50%	6.50%
Health care cost trend rate, Ultimate rate	5.00%	5.00%	5.00%
Health care cost trend rate, Year trend reaches the ultimate rate	2027	2027	2026
Postretirement Benefit Plans \| Net Periodic Benefit Cost
Defined Benefit Plan Disclosure [Line Items]
Weighted average assumptions used to determine Measurement date	Jan. 01, 2022	Jan. 01, 2021	Jan. 01, 2020
Weighted average assumptions used to determine net periodic benefit cost/(income), Discount rate	5.43%	2.60%	2.11%
Health care cost trend rate, Initial rate	7.00%	6.25%	6.50%
Health care cost trend rate, Ultimate rate	5.00%	5.00%	5.00%
Health care cost trend rate, Year trend reaches the ultimate rate	2031	2027	2027

Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Measurement Date

No definition available.

Name:	flo_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostMeasurementDate
Namespace Prefix:	flo_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Month-end measurement date applicable when an accounting policy election is made to measure plan assets and benefit obligations as of the month-end that is closest to the fiscal year-end, in YYYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanAccountingPolicyElectionMeasurementDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average rate increase of compensation, used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(3)
-URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e2919-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average rate of compensation increase used to determine net periodic benefit cost of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Assumed rate, for next fiscal year, based on annual change in cost of health care cost benefits used to measure expected cost of benefits covered by defined benefit postretirement plan. Factors include, but are not limited to, estimate of health care inflation, change in health care utilization or delivery pattern, technological advances, and change in health status of participant. Excludes factors for change in composition of plan population by age and dependency status.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Ultimate trend rate for health care cost for defined benefit postretirement plan.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Year ultimate health care cost trend rate is expected to be reached, in YYYY format.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanYearHealthCareCostTrendRateReachesUltimateTrendRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:gYearListItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_EquitySecuritiesByInvestmentObjectiveAxis=flo_BenefitObligationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_EquitySecuritiesByInvestmentObjectiveAxis=flo_NetPeriodicBenefitCostMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: