Summary of Significant Accounting Policies	12 Months Ended
Dec. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies [Text Block]	(1) Summary of Significant Accounting Policies (a)Business Publix Super Markets, Inc. and its wholly owned subsidiaries (Company) are in the business of operating retail food supermarkets in Florida, Georgia, Alabama, South Carolina, Tennessee, North Carolina and Virginia. The Company opened its first supermarket in Kentucky in January 2024. The Company was founded in 1930 and has no other significant lines of business or industry segments. (b)Principles of Consolidation The consolidated financial statements include the accounts of the Company, its wholly owned subsidiaries and certain joint ventures in which the Company has a controlling financial interest. All significant intercompany balances and transactions are eliminated in consolidation. (c)Fiscal Year The Company’s fiscal year ends on the last Saturday in December. Fiscal years 2023 and 2021 include 52 weeks and fiscal year 2022 includes 53 weeks. (d)Cash Equivalents The Company considers all liquid investments with maturities of three months or less to be cash equivalents. (e)Trade Receivables Trade receivables primarily include amounts due from vendor rebates, debit and credit card sales and pharmacy third party insurance reimbursements. (f)Inventories Inventories are valued at the lower of cost or market. The dollar value last-in, first-out (LIFO) method was used to determine the cost for 81% of inventories as of December 30, 2023 and December 31, 2022. Under this method, inventory is stated at cost, which is determined by applying a cost-to-retail ratio to each similar merchandise category’s ending retail value. The cost of the remaining inventories was determined using the first-in, first-out (FIFO) method. The FIFO cost of inventory approximates replacement or current cost. The FIFO method is used to value certain manufactured, seasonal, perishable and other miscellaneous inventory items due to fluctuating costs and inconsistent product availability. The Company also reduces inventory for estimated losses related to shrink. If all inventories were valued using the FIFO method, inventories and current assets would have been higher than reported by $893 million and $805 million as of December 30, 2023 and December 31, 2022, respectively. (g)Investments Debt securities are classified as available-for-sale and measured at fair value. The Company evaluates debt securities on an individual security basis to determine if an unrealized loss is due to a credit loss or other factors, including interest rate fluctuations. The collectability of debt securities is evaluated based on criteria that include the extent to which the cost (cost of the debt security adjusted for amortization of premium or accretion of discount) exceeds fair value, the credit rating of the issuer or security, the failure of the issuer to make scheduled principal or interest payments and the financial health and prospects of the issuer or security. Credit losses on debt securities the Company does not intend to sell and will not be required to sell prior to any anticipated recovery are recognized in earnings through an allowance. The allowance is measured as the difference between the present value of expected cash flows and the cost of the debt security, limited to the difference between the cost and the fair value of the debt security. Expected cash flows are discounted using the debt security’s effective interest rate. Subsequent changes to the allowance are recognized in earnings in the period of the change. Credit losses on debt securities the Company intends to sell or will be required to sell prior to any anticipated recovery are recognized in earnings and measured as the difference between the cost and the fair value of the debt security. Other unrealized losses on debt securities the Company does not intend to sell and will not be required to sell prior to any anticipated recovery are reported in other comprehensive earnings net of income taxes and included as a component of stockholders’ equity. Other unrealized losses on debt securities the Company intends to sell or will be required to sell prior to any anticipated recovery are recognized in earnings and measured as the difference between the cost and the fair value of the debt security. Equity securities are measured at fair value with net unrealized gains and losses from changes in the fair value recognized in earnings (fair value adjustment). Interest and dividend income, amortization of premiums, accretion of discounts and realized gains and losses on debt and equity securities are included in investment income. Interest income is accrued as earned. Dividend income is recognized as income on the ex-dividend date. The cost of debt and equity securities sold is based on the specific identification method. (h)Leases The Company conducts a major portion of its retail operations from leased locations. The Company determines whether a lease exists at inception. Initial lease terms are typically 20 years followed by five year renewal options and may include rent escalation clauses. The Company recognizes right-of-use assets and lease liabilities based on the present value of future lease payments. Future lease payments include the initial lease term and any renewal options to the extent it is reasonably certain the option will be exercised. The present value of future lease payments is determined by using the Company’s incremental borrowing rate at the time of lease commencement. The incremental borrowing rate is estimated based on a composite index of debt for similarly rated companies with comparable terms. Operating lease expense primarily represents fixed lease payments for operating leases recognized on a straight-line basis over the applicable lease term. Variable lease expense represents the payment of real estate taxes, insurance, maintenance and, for certain locations, additional rentals based on a percentage of sales in excess of stipulated minimums (excess rent). The payment of variable real estate taxes, insurance and maintenance is generally based on the Company’s pro-rata share of total shopping center square footage. The Company estimates excess rent, where applicable, based on annual sales projections and uses the straight-line method to amortize the cost. The annual sales projections are reviewed periodically and adjusted if necessary. (i)Property, Plant and Equipment and Depreciation Assets are recorded at cost and depreciated or amortized using the straight-line method over their estimated useful lives or the terms of the related leases, if shorter, as follows: buildings and improvements (10‑40 years); furniture, fixtures and equipment (3‑20 years); leasehold improvements (10‑20 years); and finance lease right-of-use assets (5‑20 years). Maintenance and repairs are expensed as incurred. Expenditures for renewals and betterments are capitalized. The gain or loss realized on disposed assets or assets to be disposed of is recorded in earnings. (j)Long-Lived Assets The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the net book value of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the net book value of an asset to the future net undiscounted cash flows expected to be generated by the asset. An impairment loss is recorded for the excess of the net book value over the fair value of the asset. The fair value is estimated based on expected discounted future cash flows. Assets to be disposed of are reported at the lower of the carrying amount or fair value less cost to sell and are no longer depreciated or amortized. Long-lived assets, including operating lease right-of-use assets, buildings and improvements, furniture, fixtures and equipment, leasehold improvements and finance lease right-of-use assets, are evaluated for impairment at the supermarket level. (k)Self-Insurance The Company is generally self-insured for claims related to health care, employee benefits, workers’ compensation, general liability, property, plant and equipment, fleet liability and directors and officers liability. The Company uses third party insurance in certain instances to partially mitigate the risk related to these potential losses. Self-insurance reserves are established for health care, workers’ compensation, general liability and fleet liability claims. These reserves are determined based on actual claims experience and an estimate of claims incurred but not reported including, where necessary, actuarial studies. Actuarial projections of losses for general liability and workers’ compensation claims are discounted. (l)Postretirement Benefit The Company provides a postretirement life insurance benefit for certain salaried and hourly full-time employees who meet the eligibility requirements. Effective January 1, 2002, the Company amended the postretirement life insurance benefit under its Group Life Insurance Plan. To receive the postretirement life insurance benefit after the amendment, an employee must have had at least five years of full-time service and the employee’s age plus years of credited service must have equaled 65 or greater as of October 1, 2001. At retirement, such employees also must be at least age 55 with at least 10 years of full-time service to be eligible to receive the postretirement life insurance benefit. Actuarial projections are used to calculate the year end postretirement benefit obligation, discounted using a yield curve methodology based on high quality bonds with a rating of AA or better. Actuarial gains and losses are amortized from accumulated other comprehensive earnings into net periodic postretirement benefit cost over future years when the accumulation of such gains or losses exceeds 10% of the year end postretirement benefit obligation. The Company included the accrued postretirement benefit obligation of $92 million and $93 million in other noncurrent liabilities on the consolidated balance sheets as of December 30, 2023 and December 31, 2022, respectively. (m)Stock Split On April 1, 2022, the Company filed Articles of Amendment to its Restated Articles of Incorporation in order to effect a 5-for-1 stock split of the Company’s common stock, par value $1.00 per share (Common Stock), and an increase in the number of authorized shares of Common Stock from 1 billion to 4 billion, effective as of the close of business April 14, 2022. The Articles of Amendment were approved by the Company’s Board of Directors on April 1, 2022. All applicable data, including share and per share amounts, in the consolidated financial statements and accompanying notes have been retroactively adjusted to give effect to the stock split. (n)Comprehensive Earnings Comprehensive earnings include net earnings and other comprehensive earnings. Other comprehensive earnings include revenues, expenses, gains and losses that have been excluded from net earnings and recorded directly to stockholders’ equity. Included in other comprehensive earnings are certain unrealized gains and losses on debt securities and adjustments to the postretirement benefit obligation net of income taxes. (o)Revenue Recognition The Company sells grocery (including dairy, produce, floral, deli, bakery, meat and seafood), health and beauty care, general merchandise, pharmacy and other products and services. Grocery was 81% of sales for 2023, 83% of sales for 2022 and 84% of sales for 2021. All other products and services were 19% of sales for 2023, 17% of sales for 2022 and 16% of sales for 2021. Revenue is recognized at the point of sale for retail sales. Customer returns are immaterial. Vendor coupons that are reimbursed are accounted for as sales. Coupons and other sales incentives offered by the Company that are not reimbursed are recorded as a reduction of sales. The Company records sales net of applicable sales taxes. (p)Other Operating Income Other operating income is recognized on a net basis as earned. Other operating income includes income generated from other activities, primarily automated teller transaction fees, licensee sales commissions, lottery commissions, mall gift card commissions, money transfer fees and vending machine commissions. (q)Cost of Merchandise Sold Cost of merchandise sold includes costs of inventory and costs related to in-store production. Cost of merchandise sold also includes inbound freight charges, purchasing and receiving costs, warehousing costs and other costs of the Company’s distribution network. Rebates received from a vendor in connection with the purchase or promotion of the vendor’s products are recognized as a reduction of cost of merchandise sold as earned. These vendor rebates are recognized as earned in accordance with the underlying agreement with the vendor and completion of the earnings process. Short-term vendor agreements with advance payment provisions are recorded as a current liability and recognized over the appropriate period as earned according to the underlying agreements. Long-term vendor agreements with advance payment provisions are recorded as a noncurrent liability and recognized over the appropriate period as earned according to the underlying agreements. (r)Advertising Costs Advertising costs are expensed as incurred and were $318 million, $317 million and $280 million for 2023, 2022 and 2021, respectively. (s)Other Nonoperating Income, net Other nonoperating income, net includes rent from tenants in owned shopping centers, net of related expenses, and other miscellaneous nonoperating income. (t)Income Taxes Deferred income taxes are established for temporary differences between financial and tax reporting bases and are subsequently adjusted to reflect changes in income tax rates expected to be in effect when the temporary differences reverse. The Company recognizes accrued interest and penalties related to income tax liabilities as a component of income tax expense. The Company invests in certain investment related tax credits that promote affordable housing and renewable energy. These investments generate a return primarily through the realization of federal and state tax credits and other tax benefits. The Company accounts for its affordable housing investments using the proportional amortization method. Under this method, the investment is amortized into income tax expense in proportion to the tax credits received and the investment tax credits are recognized as a reduction of income tax expense. The Company accounts for its renewable energy investments using the deferral method. Under this method, the investment tax credits are recognized as a reduction of the renewable energy investments. (u)Common Stock and Earnings Per Share Earnings per share is calculated by dividing net earnings by the weighted average shares outstanding. Basic and diluted earnings per share are the same because the Company does not have options or other stock compensation programs that impact the calculation of diluted earnings per share. All shares owned by the Employee Stock Ownership Plan (ESOP) are included in the earnings per share calculations. Dividends paid to the ESOP, as well as dividends on all other common stock shares, are reflected as a reduction of retained earnings. All common stock shares, including ESOP and 401(k) Plan shares, receive one vote per share and have the same dividend rights. The voting rights for ESOP shares allocated to participants’ accounts are passed through to the participants. The Trustee of the Company’s common stock in the 401(k) Plan votes the shares held in that plan. (v)Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

Publix Super Markets, Inc. and its wholly owned subsidiaries (Company) are in the business of operating retail food supermarkets in Florida, Georgia, Alabama, South Carolina, Tennessee, North Carolina and Virginia. The Company opened its first supermarket in Kentucky in January 2024. The Company was founded in 1930 and has no other significant lines of business or industry segments.

The consolidated financial statements include the accounts of the Company, its wholly owned subsidiaries and certain joint ventures in which the Company has a controlling financial interest. All significant intercompany balances and transactions are eliminated in consolidation.

Inventories are valued at the lower of cost or market. The dollar value last-in, first-out (LIFO) method was used to determine the cost for 81% of inventories as of December 30, 2023 and December 31, 2022. Under this method, inventory is stated at cost, which is determined by applying a cost-to-retail ratio to each similar merchandise category’s ending retail value. The cost of the remaining inventories was determined using the first-in, first-out (FIFO) method. The FIFO cost of inventory approximates replacement or current cost. The FIFO method is used to value certain manufactured, seasonal, perishable and other miscellaneous inventory items due to fluctuating costs and inconsistent product availability. The Company also reduces inventory for estimated losses related to shrink. If all inventories were valued using the FIFO method, inventories and current assets would have been higher than reported by $893 million and $805 million as of December 30, 2023 and December 31, 2022, respectively.

Debt securities are classified as available-for-sale and measured at fair value. The Company evaluates debt securities on an individual security basis to determine if an unrealized loss is due to a credit loss or other factors, including interest rate fluctuations. The collectability of debt securities is evaluated based on criteria that include the extent to which the cost (cost of the debt security adjusted for amortization of premium or accretion of discount) exceeds fair value, the credit rating of the issuer or security, the failure of the issuer to make scheduled principal or interest payments and the financial health and prospects of the issuer or security.

Credit losses on debt securities the Company does not intend to sell and will not be required to sell prior to any anticipated recovery are recognized in earnings through an allowance. The allowance is measured as the difference between the present value of expected cash flows and the cost of the debt security, limited to the difference between the cost and the fair value of the debt security. Expected cash flows are discounted using the debt security’s effective interest rate. Subsequent changes to the allowance are recognized in earnings in the period of the change. Credit losses on debt securities the Company intends to sell or will be required to sell prior to any anticipated recovery are recognized in earnings and measured as the difference between the cost and the fair value of the debt security.

Other unrealized losses on debt securities the Company does not intend to sell and will not be required to sell prior to any anticipated recovery are reported in other comprehensive earnings net of income taxes and included as a component of stockholders’ equity. Other unrealized losses on debt securities the Company intends to sell or will be required to sell prior to any anticipated recovery are recognized in earnings and measured as the difference between the cost and the fair value of the debt security.

Interest and dividend income, amortization of premiums, accretion of discounts and realized gains and losses on debt and equity securities are included in investment income. Interest income is accrued as earned. Dividend income is recognized as income on the ex-dividend date. The cost of debt and equity securities sold is based on the specific identification method.

The Company conducts a major portion of its retail operations from leased locations. The Company determines whether a lease exists at inception. Initial lease terms are typically 20 years followed by five year renewal options and may include rent escalation clauses. The Company recognizes right-of-use assets and lease liabilities based on the present value of future lease payments. Future lease payments include the initial lease term and any renewal options to the extent it is reasonably certain the option will be exercised. The present value of future lease payments is determined by using the Company’s incremental borrowing rate at the time of lease commencement. The incremental borrowing rate is estimated based on a composite index of debt for similarly rated companies with comparable terms.

Operating lease expense primarily represents fixed lease payments for operating leases recognized on a straight-line basis over the applicable lease term. Variable lease expense represents the payment of real estate taxes, insurance, maintenance and, for certain locations, additional rentals based on a percentage of sales in excess of stipulated minimums (excess rent). The payment of variable real estate taxes, insurance and maintenance is generally based on the Company’s pro-rata share of total shopping center square footage. The Company estimates excess rent, where applicable, based on annual sales projections and uses the straight-line method to amortize the cost. The annual sales projections are reviewed periodically and adjusted if necessary.

Assets are recorded at cost and depreciated or amortized using the straight-line method over their estimated useful lives or the terms of the related leases, if shorter, as follows: buildings and improvements (10‑40 years); furniture, fixtures and equipment (3‑20 years); leasehold improvements (10‑20 years); and finance lease right-of-use assets (5‑20 years).

The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the net book value of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the net book value of an asset to the future net undiscounted cash flows expected to be generated by the asset. An impairment loss is recorded for the excess of the net book value over the fair value of the asset. The fair value is estimated based on expected discounted future cash flows. Assets to be disposed of are reported at the lower of the carrying amount or fair value less cost to sell and are no longer depreciated or amortized. Long-lived assets, including operating lease right-of-use assets, buildings and improvements, furniture, fixtures and equipment, leasehold improvements and finance lease right-of-use assets, are evaluated for impairment at the supermarket level.

The Company is generally self-insured for claims related to health care, employee benefits, workers’ compensation, general liability, property, plant and equipment, fleet liability and directors and officers liability. The Company uses third party insurance in certain instances to partially mitigate the risk related to these potential losses. Self-insurance reserves are established for health care, workers’ compensation, general liability and fleet liability claims. These reserves are determined based on actual claims experience and an estimate of claims incurred but not reported including, where necessary, actuarial studies. Actuarial projections of losses for general liability and workers’ compensation claims are discounted.

The Company provides a postretirement life insurance benefit for certain salaried and hourly full-time employees who meet the eligibility requirements. Effective January 1, 2002, the Company amended the postretirement life insurance benefit under its Group Life Insurance Plan. To receive the postretirement life insurance benefit after the amendment, an employee must have had at least five years of full-time service and the employee’s age plus years of credited service must have equaled 65 or greater as of October 1, 2001. At retirement, such employees also must be at least age 55 with at least 10 years of full-time service to be eligible to receive the postretirement life insurance benefit.

Actuarial projections are used to calculate the year end postretirement benefit obligation, discounted using a yield curve methodology based on high quality bonds with a rating of AA or better. Actuarial gains and losses are amortized from accumulated other comprehensive earnings into net periodic postretirement benefit cost over future years when the accumulation of such gains or losses exceeds 10% of the year end postretirement benefit obligation. The Company included the accrued postretirement benefit obligation of $92 million and $93 million in other noncurrent liabilities on the consolidated balance sheets as of December 30, 2023 and December 31, 2022, respectively.

On April 1, 2022, the Company filed Articles of Amendment to its Restated Articles of Incorporation in order to effect a 5-for-1 stock split of the Company’s common stock, par value $1.00 per share (Common Stock), and an increase in the number of authorized shares of Common Stock from 1 billion to 4 billion, effective as of the close of business April 14, 2022. The Articles of Amendment were approved by the Company’s Board of Directors on April 1, 2022. All applicable data, including share and per share amounts, in the consolidated financial statements and accompanying notes have been retroactively adjusted to give effect to the stock split.

Comprehensive earnings include net earnings and other comprehensive earnings. Other comprehensive earnings include revenues, expenses, gains and losses that have been excluded from net earnings and recorded directly to stockholders’ equity. Included in other comprehensive earnings are certain unrealized gains and losses on debt securities and adjustments to the postretirement benefit obligation net of income taxes.

The Company sells grocery (including dairy, produce, floral, deli, bakery, meat and seafood), health and beauty care, general merchandise, pharmacy and other products and services. Grocery was 81% of sales for 2023, 83% of sales for 2022 and 84% of sales for 2021. All other products and services were 19% of sales for 2023, 17% of sales for 2022 and 16% of sales for 2021.

Revenue is recognized at the point of sale for retail sales. Customer returns are immaterial. Vendor coupons that are reimbursed are accounted for as sales. Coupons and other sales incentives offered by the Company that are not reimbursed are recorded as a reduction of sales. The Company records sales net of applicable sales taxes.

Other operating income is recognized on a net basis as earned. Other operating income includes income generated from other activities, primarily automated teller transaction fees, licensee sales commissions, lottery commissions, mall gift card commissions, money transfer fees and vending machine commissions.

Cost of merchandise sold includes costs of inventory and costs related to in-store production. Cost of merchandise sold also includes inbound freight charges, purchasing and receiving costs, warehousing costs and other costs of the Company’s distribution network.

Rebates received from a vendor in connection with the purchase or promotion of the vendor’s products are recognized as a reduction of cost of merchandise sold as earned. These vendor rebates are recognized as earned in accordance with the underlying agreement with the vendor and completion of the earnings process. Short-term vendor agreements with advance payment provisions are recorded as a current liability and recognized over the appropriate period as earned according to the underlying agreements. Long-term vendor agreements with advance payment provisions are recorded as a noncurrent liability and recognized over the appropriate period as earned according to the underlying agreements.

Deferred income taxes are established for temporary differences between financial and tax reporting bases and are subsequently adjusted to reflect changes in income tax rates expected to be in effect when the temporary differences reverse. The Company recognizes accrued interest and penalties related to income tax liabilities as a component of income tax expense. The Company invests in certain investment related tax credits that promote affordable housing and renewable energy. These investments generate a return primarily through the realization of federal and state tax credits and other tax benefits. The Company accounts for its affordable housing investments using the proportional amortization method. Under this method, the investment is amortized into income tax expense in proportion to the tax credits received and the investment tax credits are recognized as a reduction of income tax expense. The Company accounts for its renewable energy investments using the deferral method. Under this method, the investment tax credits are recognized as a reduction of the renewable energy investments.

Earnings per share is calculated by dividing net earnings by the weighted average shares outstanding. Basic and diluted earnings per share are the same because the Company does not have options or other stock compensation programs that impact the calculation of diluted earnings per share. All shares owned by the Employee Stock Ownership Plan (ESOP) are included in the earnings per share calculations. Dividends paid to the ESOP, as well as dividends on all other common stock shares, are reflected as a reduction of retained earnings. All common stock shares, including ESOP and 401(k) Plan shares, receive one vote per share and have the same dividend rights. The voting rights for ESOP shares allocated to participants’ accounts are passed through to the participants. The Trustee of the Company’s common stock in the 401(k) Plan votes the shares held in that plan.

The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.