General (Policies)	6 Months Ended
Jun. 30, 2022
Accounting Policies [Abstract]
Basis of Accounting	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with the instructions to Form 10-Q and therefore do not include all information and footnotes required by accounting principles generally accepted in the U.S. (“U.S. GAAP”) for complete financial statements. Except as disclosed herein, there have been no material changes in the information disclosed in the notes to the consolidated financial statements included in the Annual Report on Form 10-K of Genuine Parts Company (the “Company,” “we,” “our,” “us,” or “its”) for the year ended December 31, 2021. Accordingly, the unaudited condensed consolidated financial statements and related disclosures herein should be read in conjunction with our 2021 Annual Report on Form 10-K. Significant accounting policies and other disclosures normally provided have been omitted since they are disclosed in our Annual Report and have not changed.
Use of Estimates	The preparation of interim financial statements requires management to make estimates and assumptions that affect the amounts reported in the unaudited condensed consolidated financial statements. Specifically, we make estimates and assumptions in our unaudited condensed consolidated financial statements for inventory adjustments, the accrual of bad debts, credit losses on guaranteed loans, customer sales returns, and volume incentives earned, among others. Inventory adjustments (including adjustments for a majority of inventories that are valued under the last-in, first-out (“LIFO”) method) are accrued on an interim basis and adjusted in the fourth quarter based on the annual book to physical inventory adjustment and LIFO valuation. Reserves for bad debts, credit losses on guaranteed loans and customer sales returns are estimated and accrued on an interim basis based on a consideration of historical experience, current conditions, and reasonable and supportable forecasts. Volume incentives are estimated based upon cumulative and projected purchasing levels. In the opinion of management, all adjustments necessary for a fair presentation of our financial results for the interim periods have been made. These adjustments are of a normal recurring nature. We have reclassified certain prior period amounts to conform to the current period presentation.
Recent Accounting Pronouncements	Changes to U.S. GAAP are established by the Financial Accounting Standards Board (“FASB”) in the form of Accounting Standards Updates (“ASU”) to the FASB Accounting Standards Codification (“ASC”). We consider the applicability and impact of all ASUs and have determined that any recently adopted accounting pronouncements did not have a material impact on our condensed consolidated financial statements and all recent accounting pronouncements not yet adopted are not applicable or are expected to have an immaterial impact on our condensed consolidated financial statements.
Guarantees	We guarantee the borrowings of certain independently controlled automotive parts stores and businesses (“independents”) and certain other affiliates in which we have a noncontrolling equity ownership interest (“affiliates”). While such borrowings of the independents and affiliates are outstanding, we are required to maintain compliance with certain covenants. At June 30, 2022, we were in compliance with all such covenants.As of June 30, 2022, there are no material guaranteed loans for which the borrower is experiencing financial difficulty and recovery is expected to be provided substantially through the operation or sale of the collateral.

The preparation of interim financial statements requires management to make estimates and assumptions that affect the amounts reported in the unaudited condensed consolidated financial statements. Specifically, we make estimates and assumptions in our unaudited condensed consolidated financial statements for inventory adjustments, the accrual of bad debts, credit losses on guaranteed loans, customer sales returns, and volume incentives earned, among others. Inventory adjustments (including adjustments for a majority of inventories that are valued under the last-in, first-out (“LIFO”) method) are accrued on an interim basis and adjusted in the fourth quarter based on the annual book to physical inventory adjustment and LIFO valuation. Reserves for bad debts, credit losses on guaranteed loans and customer sales returns are estimated and accrued on an interim basis based on a consideration of historical experience, current conditions, and reasonable and supportable forecasts. Volume incentives are estimated based upon cumulative and projected purchasing levels. In the opinion of management, all adjustments necessary for a fair presentation of our financial results for the interim periods have been made. These adjustments are of a normal recurring nature. We have reclassified certain prior period amounts to conform to the current period presentation.

We guarantee the borrowings of certain independently controlled automotive parts stores and businesses (“independents”) and certain other affiliates in which we have a noncontrolling equity ownership interest (“affiliates”). While such borrowings of the independents and affiliates are outstanding, we are required to maintain compliance with certain covenants. At June 30, 2022, we were in compliance with all such covenants.As of June 30, 2022, there are no material guaranteed loans for which the borrower is experiencing financial difficulty and recovery is expected to be provided substantially through the operation or sale of the collateral.