Summary of Significant Accounting Policies (Policies)	9 Months Ended
Apr. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements of Donaldson Company, Inc. and its subsidiaries (the Company) have been prepared in accordance with generally accepted accounting principles in the United States (U.S. GAAP) and the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and notes required for complete financial statements. In the opinion of management, all adjustments considered necessary for a fair statement of earnings, comprehensive income, financial position and cash flows have been included and are of a normal recurring nature. Operating results for the three and nine month periods ended April 30, 2016, are not necessarily indicative of the results that may be expected for future periods. The year-end condensed balance sheet data was derived from the Company's audited financial statements but does not include all disclosures required by U.S. GAAP. For further information, refer to the Audited Consolidated Financial Statements and Notes thereto included in the Company’s Annual Report on Form 10-K for the year ended July 31, 2015.
New Accounting Standards Not Yet Adopted	New Accounting Standards Not Yet Adopted In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers (Topic 606) (ASU 2014-09), which amended revenue recognition guidance to clarify the principles for recognizing revenue from contracts with Customers. The guidance requires an entity to recognize revenue to depict the transfer of goods or services to Customers in an amount that reflects the consideration to which an entity expects to be entitled in exchange for those goods or services. The guidance also requires expanded disclosures relating to the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with Customers. Additionally, qualitative and quantitative disclosures are required about Customer contracts, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. This accounting guidance is effective for the Company beginning in the first quarter of Fiscal 2019 using one of two prescribed retrospective methods. Early adoption is permitted. The Company is evaluating the impact that ASU 2014-09 will have on the Company’s consolidated financial statements. In June 2014, the FASB issued ASU 2014-12, Compensation – Stock Compensation (Topic 718): Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could be Achieved after the Requisite Service Period (ASU 2014-12), which amended guidance related to share-based payments where terms of the award provide that a performance target could be achieved after the requisite service period. This accounting guidance is effective for the Company beginning in the first quarter of Fiscal 2018. The Company is evaluating the impact that ASU 2014-12 will have on the Company’s consolidated financial statements. In April 2015, the FASB issued ASU 2015-03, Interest – Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs (ASU 2015-03), which amended guidance requiring the issuance of debt costs related to a recognized debt liability be presented on the balance sheet as a direct deduction from the amount of the debt liability, consistent with debt discounts and premiums. This accounting guidance is effective for the Company beginning in the first quarter of Fiscal 2017. Early adoption is permitted. The Company is evaluating the impact that ASU 2015-03 will have on the Company’s consolidated financial statements. In May 2015, FASB issued ASU 2015-07, Fair Value Measurement (Topic 850): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (ASU 2015-07), which amended guidance requiring a company to categorize investments for which fair values are measured using the net asset value (NAV) per share practical expedient. ASU 2015-07 also limits the disclosures to investments for which the entity has elected to measure the fair value using the practical expedient. This accounting guidance is effective for the Company beginning in the first quarter of Fiscal 2017. Early adoption is permitted. The Company does not expect the application of ASU 2015-07 to have a significant impact on its consolidated financial statements. The Company expects ASU 2015-07 only to affect the Company's disclosures. In July 2015, the FASB issued ASU 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory (ASU 2015-11), which amended the guidance requiring companies not using the last-in, first-out (LIFO) method to measure inventory at the lower of cost and net realizable value rather than the lower of cost or market. This accounting guidance is effective for the Company beginning in the first quarter of Fiscal 2017. Early adoption is permitted. The Company does not expect the application of ASU 2015-11 to have a significant impact on its consolidated financial statements. In September 2015, the FASB issued ASU 2015-16, Simplifying the Accounting for Measurement-Period Adjustments, which amends (Topic 805) Business Combinations. This ASU requires that acquiring entities recognize measurement period adjustments in the reporting period the amounts are determined, including earnings adjustments that would have been recorded in previous periods if the adjustments were known at the acquisition date. Acquiring entities are no longer required to retrospectively adjust amounts in comparative periods. The adjustment amounts and reasons are still disclosed. The Company does not expect the application of ASU 2015-16 to have a significant impact on its consolidated financial statements. In November 2015, the FASB issued ASU 2015-17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes (ASU 2015-17), which amended the guidance requiring companies to separate deferred income tax liabilities and assets into current and non-current amounts in a classified statement of financial position. This accounting guidance simplifies the presentation of deferred income taxes, such that deferred tax liabilities and assets be classified as non-current in a classified statement of financial position. This accounting guidance is effective for the Company beginning in the first quarter of Fiscal 2018. Early adoption is permitted. The Company is evaluating the impact that ASU 2015-17 will have on the Company's consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (ASU 2016-02), which amended the guidance requiring companies to recognize assets and liabilities for leases with lease terms of more than twelve months. The new guidance will require companies to record both capital and operating leases on the balance sheet. This accounting guidance is effective for the Company beginning in the first quarter of Fiscal 2020 on a modified retrospective basis, and early adoption is permitted. The Company is evaluating the impact that ASU 2016-02 will have on its consolidated financial statements.

New Accounting Standards Not Yet Adopted In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers (Topic 606) (ASU 2014-09), which amended revenue recognition guidance to clarify the principles for recognizing revenue from contracts with Customers. The guidance requires an entity to recognize revenue to depict the transfer of goods or services to Customers in an amount that reflects the consideration to which an entity expects to be entitled in exchange for those goods or services. The guidance also requires expanded disclosures relating to the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with Customers. Additionally, qualitative and quantitative disclosures are required about Customer contracts, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. This accounting guidance is effective for the Company beginning in the first quarter of Fiscal 2019 using one of two prescribed retrospective methods. Early adoption is permitted. The Company is evaluating the impact that ASU 2014-09 will have on the Company’s consolidated financial statements.

In June 2014, the FASB issued ASU 2014-12, Compensation – Stock Compensation (Topic 718): Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could be Achieved after the Requisite Service Period (ASU 2014-12), which amended guidance related to share-based payments where terms of the award provide that a performance target could be achieved after the requisite service period. This accounting guidance is effective for the Company beginning in the first quarter of Fiscal 2018. The Company is evaluating the impact that ASU 2014-12 will have on the Company’s consolidated financial statements.

In April 2015, the FASB issued ASU 2015-03, Interest – Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs (ASU 2015-03), which amended guidance requiring the issuance of debt costs related to a recognized debt liability be presented on the balance sheet as a direct deduction from the amount of the debt liability, consistent with debt discounts and premiums. This accounting guidance is effective for the Company beginning in the first quarter of Fiscal 2017. Early adoption is permitted. The Company is evaluating the impact that ASU 2015-03 will have on the Company’s consolidated financial statements.

In May 2015, FASB issued ASU 2015-07, Fair Value Measurement (Topic 850): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (ASU 2015-07), which amended guidance requiring a company to categorize investments for which fair values are measured using the net asset value (NAV) per share practical expedient. ASU 2015-07 also limits the disclosures to investments for which the entity has elected to measure the fair value using the practical expedient. This accounting guidance is effective for the Company beginning in the first quarter of Fiscal 2017. Early adoption is permitted. The Company does not expect the application of ASU 2015-07 to have a significant impact on its consolidated financial statements. The Company expects ASU 2015-07 only to affect the Company's disclosures.

In July 2015, the FASB issued ASU 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory (ASU 2015-11), which amended the guidance requiring companies not using the last-in, first-out (LIFO) method to measure inventory at the lower of cost and net realizable value rather than the lower of cost or market. This accounting guidance is effective for the Company beginning in the first quarter of Fiscal 2017. Early adoption is permitted. The Company does not expect the application of ASU 2015-11 to have a significant impact on its consolidated financial statements.

In September 2015, the FASB issued ASU 2015-16, Simplifying the Accounting for Measurement-Period Adjustments, which amends (Topic 805) Business Combinations. This ASU requires that acquiring entities recognize measurement period adjustments in the reporting period the amounts are determined, including earnings adjustments that would have been recorded in previous periods if the adjustments were known at the acquisition date. Acquiring entities are no longer required to retrospectively adjust amounts in comparative periods. The adjustment amounts and reasons are still disclosed. The Company does not expect the application of ASU 2015-16 to have a significant impact on its consolidated financial statements.

In November 2015, the FASB issued ASU 2015-17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes (ASU 2015-17), which amended the guidance requiring companies to separate deferred income tax liabilities and assets into current and non-current amounts in a classified statement of financial position. This accounting guidance simplifies the presentation of deferred income taxes, such that deferred tax liabilities and assets be classified as non-current in a classified statement of financial position. This accounting guidance is effective for the Company beginning in the first quarter of Fiscal 2018. Early adoption is permitted. The Company is evaluating the impact that ASU 2015-17 will have on the Company's consolidated financial statements.

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (ASU 2016-02), which amended the guidance requiring companies to recognize assets and liabilities for leases with lease terms of more than twelve months. The new guidance will require companies to record both capital and operating leases on the balance sheet. This accounting guidance is effective for the Company beginning in the first quarter of Fiscal 2020 on a modified retrospective basis, and early adoption is permitted. The Company is evaluating the impact that ASU 2016-02 will have on its consolidated financial statements.