General (Policies)	9 Months Ended
Sep. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation	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 items disclosed in our Annual Report have been omitted from this report because they 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. In September 2022, the FASB issued ASU 2022-04, Liabilities-Supplier Finance Programs. This standard requires disclosure of the key terms of outstanding supply chain finance programs and a rollforward of the related amounts due to vendors participating in these programs. The new standard does not affect the recognition, measurement or financial statement presentation of any amounts due. The guidance is effective in the first quarter of 2023, except for the rollforward, which is effective in the first quarter of 2024. Early adoption is permitted. We are evaluating the adoption of this new guidance.
Derivatives and Hedging	We are exposed to various risks arising from business operations and market conditions, including fluctuations in interest rates and certain foreign currencies. When deemed appropriate, we use derivative and non-derivative instruments as risk management tools to mitigate the potential impact of interest rate and foreign exchange rate risks. The objective of using these tools is to reduce fluctuations in our earnings and cash flows associated with changes in these rates. Derivative instruments are recognized in the condensed consolidated balance sheets at fair value and are designated as Level 2 in the fair value hierarchy. They are valued using inputs other than quoted prices, such as foreign exchange rates and yield curves.
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 September 30, 2022, we were in compliance with all such covenants.As of September 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.

General (Policies)

9 Months Ended

Sep. 30, 2022

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 items disclosed in our Annual Report have been omitted from this report because they 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.

In September 2022, the FASB issued ASU 2022-04, Liabilities-Supplier Finance Programs. This standard requires disclosure of the key terms of outstanding supply chain finance programs and a rollforward of the related amounts due to vendors participating in these programs. The new standard does not affect the recognition, measurement or financial statement presentation of any amounts due. The guidance is effective in the first quarter of 2023, except for the rollforward, which is effective in the first quarter of 2024. Early adoption is permitted. We are evaluating the adoption of this new guidance.

Derivatives and Hedging

We are exposed to various risks arising from business operations and market conditions, including fluctuations in interest rates and certain foreign currencies. When deemed appropriate, we use derivative and non-derivative instruments as risk management tools to mitigate the potential impact of interest rate and foreign exchange rate risks. The objective of using these tools is to reduce fluctuations in our earnings and cash flows associated with changes in these rates. Derivative instruments are recognized in the condensed consolidated balance sheets at fair value and are designated as Level 2 in the fair value hierarchy. They are valued using inputs other than quoted prices, such as foreign exchange rates and yield curves.

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 September 30, 2022, we were in compliance with all such covenants.As of September 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.