Organization, Basis of Presentation and Significant Accounting Policies (Policies)	3 Months Ended
Nov. 30, 2018
Accounting Policies [Abstract]
Consolidation, Policy	Our consolidated financial statements include the accounts of CHS and all of our wholly owned and majority owned subsidiaries. The effects of all significant intercompany transactions have been eliminated. These unaudited consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto for the year ended August 31, 2018, included in our Annual Report on Form 10-K, filed with the Securities and Exchange Commission (the "SEC").
Recent Accounting Pronouncements	Recent Accounting Pronouncements Adopted In March 2017, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update ("ASU") No. 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Costs and Net Postretirement Benefit Cost. This ASU changes the presentation of net periodic pension cost and net periodic postretirement benefit cost in the Consolidated Statements of Operations. This ASU provides that the service cost component should be included in the same income statement line item as other compensation costs arising from services rendered by the employees during the period. The other components of net periodic benefit cost (such as interest, expected return on plan assets, prior service cost amortization and actuarial gain/loss amortization) are required to be presented in the Consolidated Statements of Operations separately outside of operating income. Additionally, only service cost may be capitalized in assets. This ASU was effective for us beginning September 1, 2018, for our fiscal year 2019 and for interim periods within that fiscal year. The guidance on the presentation of the components of net periodic benefit cost in the Consolidated Statements of Operations has been applied retrospectively, and the guidance regarding the capitalization of the service cost component in assets has been applied prospectively. The adoption of this guidance had no impact on previously reported income (loss) before income taxes or net income attributable to CHS; however, non-service cost components of net periodic benefit costs in prior periods have been reclassified from operating expenses and are now reported outside of operating income within other (income) loss. Specifically, the retrospective adjustments recorded as a result of the adoption of this guidance resulted in an increase to cost of goods sold and marketing, general and administrative expense of $0.3 million and $0.8 million, respectively, and a corresponding increase of $1.2 million to other income during the three months ended November 30, 2017. There was no impact to previously reported income before income taxes and net income attributable to CHS as a result of adoption. The adoption of this amended guidance did not have a material impact on our consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business. The amendments within this ASU narrow the existing definition of a business and provide a more robust framework for evaluating whether a transaction should be accounted for as an acquisition (or disposal) of assets or a business. The definition of a business impacts various areas of accounting, including acquisitions, disposals and goodwill. Under the new guidance, fewer acquisitions are expected to be considered businesses. This ASU was effective for us beginning September 1, 2018, for our fiscal year 2019 and for interim periods within that fiscal year. The guidance has been applied prospectively. The adoption of this amended guidance did not have a material impact on our consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. This ASU requires restricted cash and restricted cash equivalents to be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the Consolidated Statements of Cash Flows as well as disclosure about the nature of restrictions on cash, cash equivalents and amounts generally described as restricted cash. Additionally, the guidance requires disclosure of the total amount of cash, cash equivalents and restricted cash for each comparative period for which a Consolidated Balance Sheet is presented. This ASU was effective for us beginning September 1, 2018, for our fiscal year 2019 and for interim periods within that fiscal year. The amendments in this ASU were applied retrospectively to all periods presented. Refer to the additional disclosures pertaining to restricted cash within the Restricted Cash significant accounting policy above. The adoption of this amended guidance did not have a material impact on our Consolidated Statements of Cash Flows. In January 2016, the FASB issued ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, which requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income. This guidance eliminates the previous cost method of accounting for certain equity securities that did not have readily determinable fair values. This guidance also simplifies the impairment assessment and allows for a fair value measurement alternative for equity investments without readily determinable fair values and includes presentation and disclosure changes. This ASU was effective for us beginning September 1, 2018, for our fiscal year 2019 and for interim periods within that fiscal year and was applied following a prospective basis. We have elected to utilize the measurement alternative for equity investments that do not have readily determinable fair values and measure these investments at cost less impairment plus or minus observable price changes in orderly transactions. As a result of the adoption of this amended guidance, we reclassified approximately $4.7 million from accumulated other comprehensive loss to the opening balance of capital reserves within our Consolidated Balance Sheet as of September 1, 2018, which did not have a material impact on our consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. This ASU is intended to reduce existing diversity in practice in how certain cash receipts and payments are presented and classified in the Consolidated Statements of Cash Flows. This ASU was effective for us beginning September 1, 2018, for our fiscal year 2019 and for interim periods within that fiscal year. The adoption of this amended guidance did not have a material impact on our Consolidated Statements of Cash Flows. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The amendments within this ASU, as well as within the additional clarifying ASUs issued by the FASB, provide a single comprehensive model to be used to determine the measurement of revenue and timing of recognition for revenue arising from contracts with customers. The core principle of the amended guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The new revenue recognition guidance includes a five-step model for the recognition of revenue, including (1) identifying the contract with a customer, (2) identifying the performance obligations in the contract, (3) determining the transaction price, (4) allocating the transaction price to the performance obligations, and (5) recognizing revenue when (or as) an entity satisfies a performance obligation. This ASU was effective for us beginning September 1, 2018, for our fiscal year 2019 and for interim periods within that fiscal year, and we elected to apply the modified retrospective method of adoption to all contracts as of the date of initial application. The majority of our revenues are attributable to forward commodity sales contracts, which are considered to be physically settled derivatives under ASC 815, Derivatives and Hedging (Topic 815). Revenues arising from derivative contracts accounted for under ASC 815 are specifically outside the scope of ASC Topic 606 and therefore not subject to the provisions of the new revenue recognition guidance. As such, the impact of adoption of the new revenue guidance has only been assessed for our revenue contracts that are not accounted for as derivative arrangements. The primary impact of adoption was changes to the timing of revenue recognition for certain revenue streams that had an immaterial impact. Following the modified retrospective method of adoption, we determined the cumulative effect of adoption for all contracts with customers that had not been completed as of the adoption date was less than $1.0 million. Additionally, the impact of applying ASC Topic 606 compared to previous guidance during the three months ended November 30, 2018, was an overall decrease to revenues of $13.1 million. Our revenue recognition accounting policy and additional information related to our revenue streams and related performance obligations required to be satisfied in order to recognize revenue can be found within Note 3, Revenues. Not Yet Adopted In August 2018, the FASB issued ASU No. 2018-15, Intangibles - Goodwill and Other - Internal-Use Software: Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. This ASU reduces the complexity of accounting for implementation, setup, and other upfront costs incurred in a cloud computing service arrangement that is hosted by a vendor. This ASU aligns the accounting for implementation costs of hosting arrangements, irrespective of whether the arrangements convey a license to the hosted software. This ASU permits either a prospective or retrospective transition approach. This ASU is effective for us beginning September 1, 2020, for our fiscal year 2021 and for interim periods within that fiscal year, with early adoption permitted. The adoption of this amended guidance is not expected to have a material impact on our consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-14, Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans, which amends ASC 715-20, Compensation - Retirement Benefits - Defined Benefit Plans - General. This ASU modifies the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans by removing and adding certain disclosures for these plans. The eliminated disclosures include (a) the amounts in accumulated other comprehensive income expected to be recognized in net periodic benefit costs over the next fiscal year and (b) the effects of a one-percentage-point change in assumed health care cost trend rates on the net periodic benefit costs and the benefit obligation for postretirement health care benefits. The new disclosures include the interest crediting rates for cash balance plans and an explanation of significant gains and losses related to changes in benefit obligations. This ASU is effective for us beginning September 1, 2021, for our fiscal year 2022 and for interim periods within that fiscal year, with early adoption permitted. The adoption of this amended guidance is not expected to have a material impact on our consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-13, Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement, which amends ASC 820, Fair Value Measurement. This ASU modifies the disclosure requirements for fair value measurements by removing, modifying and adding certain disclosures. Specifically, the guidance removes the requirement to disclose the amount and reasons for any transfers between Level 1 and Level 2 of the fair value hierarchy and removes the requirement to disclose a description of the valuation processes used to value Level 3 fair value measurements. The guidance also requires additional disclosures surrounding Level 3 changes in unrealized gains/losses included in other comprehensive income as well as the range and weighted average significant unobservable inputs calculation. This ASU is effective for us beginning September 1, 2020, for our fiscal year 2021 and for interim periods within that fiscal year. Early adoption is permitted. We elected to remove the disclosures permitted by ASU No. 2018-13 during the fourth quarter of fiscal 2018 but have not early adopted the new required additional disclosures, which is permitted by the guidance. The adoption of this amended guidance is not expected to have a material impact on our consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The amendments in this ASU introduce a new approach, based on expected losses, to estimate credit losses on certain types of financial instruments. This ASU is intended to provide financial statement users with more decision-useful information about the expected credit losses associated with most financial assets measured at amortized cost and certain other instruments, including trade and other receivables, loans, held-to-maturity debt securities, net investments in leases, and off-balance-sheet credit exposures. Entities are required to apply the provisions of this ASU as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. This ASU is effective for us beginning September 1, 2020, for our fiscal year 2021 and for interim periods within that fiscal year. We are currently evaluating the impact the adoption will have on our consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which replaces the existing guidance within ASC 840 - Leases. The amendments within this ASU, as well as within additional clarifying ASUs issued by the FASB, introduce a lessee model requiring entities to recognize assets and liabilities for most leases, but continue recognizing the associated expenses in a manner similar to existing accounting guidance. In July 2018, the FASB issued ASU No. 2018-10, Codification Improvements to Topic 842, Leases, which amends ASU No. 2016-02, Leases. This ASU is effective for us beginning September 1, 2019, for our fiscal year 2020 and for interim periods within that fiscal year. We have initiated our assessment of the new lease standard, including the utilization of surveys to gather more information about existing leases and the implementation of a new lease software to improve the collection, maintenance and aggregation of lease data necessary for the expanded reporting and disclosure requirements under the new lease standard. It is expected that the primary impact upon adoption will be the recognition, on a discounted basis, of our minimum commitments under noncancelable operating leases as right of use assets and liabilities on our Consolidated Balance Sheets. This will result in a significant increase in assets and liabilities recorded on our Consolidated Balance Sheets. Although we expect the new lease guidance will have a material impact on our Consolidated Balance Sheets, we are continuing to evaluate the practical expedient guidance provisions available and the extent of potential impacts on our consolidated financial statements, processes and internal controls.

Recent Accounting Pronouncements

Adopted

In March 2017, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update ("ASU") No. 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Costs and Net Postretirement Benefit Cost. This ASU changes the presentation of net periodic pension cost and net periodic postretirement benefit cost in the Consolidated Statements of Operations. This ASU provides that the service cost component should be included in the same income statement line item as other compensation costs arising from services rendered by the employees during the period. The other components of net periodic benefit cost (such as interest, expected return on plan assets, prior service cost amortization and actuarial gain/loss amortization) are required to be presented in the Consolidated Statements of Operations separately outside of operating income. Additionally, only service cost may be capitalized in assets. This ASU was effective for us beginning September 1, 2018, for our fiscal year 2019 and for interim periods within that fiscal year. The guidance on the presentation of the components of net periodic benefit cost in the Consolidated Statements of Operations has been applied retrospectively, and the guidance regarding the capitalization of the service cost component in assets has been applied prospectively. The adoption of this guidance had no impact on previously reported income (loss) before income taxes or net income attributable to CHS; however, non-service cost components of net periodic benefit costs in prior periods have been reclassified from operating expenses and are now reported outside of operating income within other (income) loss. Specifically, the retrospective adjustments recorded as a result of the adoption of this guidance resulted in an increase to cost of goods sold and marketing, general and administrative expense of $0.3 million and $0.8 million, respectively, and a corresponding increase of $1.2 million to other income during the three months ended November 30, 2017. There was no impact to previously reported income before income taxes and net income attributable to CHS as a result of adoption. The adoption of this amended guidance did not have a material impact on our consolidated financial statements.

In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business. The amendments within this ASU narrow the existing definition of a business and provide a more robust framework for evaluating whether a transaction should be accounted for as an acquisition (or disposal) of assets or a business. The definition of a business impacts various areas of accounting, including acquisitions, disposals and goodwill. Under the new guidance, fewer acquisitions are expected to be considered businesses. This ASU was effective for us beginning September 1, 2018, for our fiscal year 2019 and for interim periods within that fiscal year. The guidance has been applied prospectively. The adoption of this amended guidance did not have a material impact on our consolidated financial statements.

In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. This ASU requires restricted cash and restricted cash equivalents to be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the Consolidated Statements of Cash Flows as well as disclosure about the nature of restrictions on cash, cash equivalents and amounts generally described as restricted cash. Additionally, the guidance requires disclosure of the total amount of cash, cash equivalents and restricted cash for each comparative period for which a Consolidated Balance Sheet is presented. This ASU was effective for us beginning September 1, 2018, for our fiscal year 2019 and for interim periods within that fiscal year. The amendments in this ASU were applied retrospectively to all periods presented. Refer to the additional disclosures pertaining to restricted cash within the Restricted Cash significant accounting policy above. The adoption of this amended guidance did not have a material impact on our Consolidated Statements of Cash Flows.

In January 2016, the FASB issued ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, which requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income. This guidance eliminates the previous cost method of accounting for certain equity securities that did not have readily determinable fair values. This guidance also simplifies the impairment assessment and allows for a fair value measurement alternative for equity investments without readily determinable fair values and includes presentation and disclosure changes. This ASU was effective for us beginning September 1, 2018, for our fiscal year 2019 and for interim periods within that fiscal year and was applied following a prospective basis. We have elected to utilize the measurement alternative for equity investments that do not have readily determinable fair values and measure these investments at cost less impairment plus or minus observable price changes in orderly transactions. As a result of the adoption of this amended guidance, we reclassified approximately $4.7 million from accumulated other comprehensive loss to the opening balance of capital reserves within our Consolidated Balance Sheet as of September 1, 2018, which did not have a material impact on our consolidated financial statements.

In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. This ASU is intended to reduce existing diversity in practice in how certain cash receipts and payments are presented and classified in the Consolidated Statements of Cash Flows. This ASU was effective for us beginning September 1, 2018, for our fiscal year 2019 and for interim periods within that fiscal year. The adoption of this amended guidance did not have a material impact on our Consolidated Statements of Cash Flows.

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The amendments within this ASU, as well as within the additional clarifying ASUs issued by the FASB, provide a single comprehensive model to be used to determine the measurement of revenue and timing of recognition for revenue arising from contracts with customers. The core principle of the amended guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The new revenue recognition guidance includes a five-step model for the recognition of revenue, including (1) identifying the contract with a customer, (2) identifying the performance obligations in the contract, (3) determining the transaction price, (4) allocating the transaction price to the performance obligations, and (5) recognizing revenue when (or as) an entity satisfies a performance obligation. This ASU was effective for us beginning September 1, 2018, for our fiscal year 2019 and for interim periods within that fiscal year, and we elected to apply the modified retrospective method of adoption to all contracts as of the date of initial application. The majority of our revenues are attributable to forward commodity sales contracts, which are considered to be physically settled derivatives under ASC 815, Derivatives and Hedging (Topic 815). Revenues arising from derivative contracts accounted for under ASC 815 are specifically outside the scope of ASC Topic 606 and therefore not subject to the provisions of the new revenue recognition guidance. As such, the impact of adoption of the new revenue guidance has only been assessed for our revenue contracts that are not accounted for as derivative arrangements. The primary impact of adoption was changes to the timing of revenue recognition for certain revenue streams that had an immaterial impact. Following the modified retrospective method of adoption, we determined the cumulative effect of adoption for all contracts with customers that had not been completed as of the adoption date was less than $1.0 million. Additionally, the impact of applying ASC Topic 606 compared to previous guidance during the three months ended November 30, 2018, was an overall decrease to revenues of $13.1 million. Our revenue recognition accounting policy and additional information related to our revenue streams and related performance obligations required to be satisfied in order to recognize revenue can be found within Note 3, Revenues.

Not Yet Adopted

In August 2018, the FASB issued ASU No. 2018-15, Intangibles - Goodwill and Other - Internal-Use Software: Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. This ASU reduces the complexity of accounting for implementation, setup, and other upfront costs incurred in a cloud computing service arrangement that is hosted by a vendor. This ASU aligns the accounting for implementation costs of hosting arrangements, irrespective of whether the arrangements convey a license to the hosted software. This ASU permits either a prospective or retrospective transition approach. This ASU is effective for us beginning September 1, 2020, for our fiscal year 2021 and for interim periods within that fiscal year, with early adoption permitted. The adoption of this amended guidance is not expected to have a material impact on our consolidated financial statements.

In August 2018, the FASB issued ASU No. 2018-14, Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans, which amends ASC 715-20, Compensation - Retirement Benefits - Defined Benefit Plans - General. This ASU modifies the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans by removing and adding certain disclosures for these plans. The eliminated disclosures include (a) the amounts in accumulated other comprehensive income expected to be recognized in net periodic benefit costs over the next fiscal year and (b) the effects of a one-percentage-point change in assumed health care cost trend rates on the net periodic benefit costs and the benefit obligation for postretirement health care benefits. The new disclosures include the interest crediting rates for cash balance plans and an explanation of significant gains and losses related to changes in benefit obligations. This ASU is effective for us beginning September 1, 2021, for our fiscal year 2022 and for interim periods within that fiscal year, with early adoption permitted. The adoption of this amended guidance is not expected to have a material impact on our consolidated financial statements.

In August 2018, the FASB issued ASU No. 2018-13, Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement, which amends ASC 820, Fair Value Measurement. This ASU modifies the disclosure requirements for fair value measurements by removing, modifying and adding certain disclosures. Specifically, the guidance removes the requirement to disclose the amount and reasons for any transfers between Level 1 and Level 2 of the fair value hierarchy and removes the requirement to disclose a description of the valuation processes used to value Level 3 fair value measurements. The guidance also requires additional disclosures surrounding Level 3 changes in unrealized gains/losses included in other comprehensive income as well as the range and weighted average significant unobservable inputs calculation. This ASU is effective for us beginning September 1, 2020, for our fiscal year 2021 and for interim periods within that fiscal year. Early adoption is permitted. We elected to remove the disclosures permitted by ASU No. 2018-13 during the fourth quarter of fiscal 2018 but have not early adopted the new required additional disclosures, which is permitted by the guidance. The adoption of this amended guidance is not expected to have a material impact on our consolidated financial statements.

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The amendments in this ASU introduce a new approach, based on expected losses, to estimate credit losses on certain types of financial instruments. This ASU is intended to provide financial statement users with more decision-useful information about the expected credit losses associated with most financial assets measured at amortized cost and certain other instruments, including trade and other receivables, loans, held-to-maturity debt securities, net investments in leases, and off-balance-sheet credit exposures. Entities are required to apply the provisions of this ASU as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. This ASU is effective for us beginning September 1, 2020, for our fiscal year 2021 and for interim periods within that fiscal year. We are currently evaluating the impact the adoption will have on our consolidated financial statements.

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which replaces the existing guidance within ASC 840 - Leases. The amendments within this ASU, as well as within additional clarifying ASUs issued by the FASB, introduce a lessee model requiring entities to recognize assets and liabilities for most leases, but continue recognizing the associated expenses in a manner similar to existing accounting guidance. In July 2018, the FASB issued ASU No. 2018-10, Codification Improvements to Topic 842, Leases, which amends ASU No. 2016-02, Leases. This ASU is effective for us beginning September 1, 2019, for our fiscal year 2020 and for interim periods within that fiscal year. We have initiated our assessment of the new lease standard, including the utilization of surveys to gather more information about existing leases and the implementation of a new lease software to improve the collection, maintenance and aggregation of lease data necessary for the expanded reporting and disclosure requirements under the new lease standard. It is expected that the primary impact upon adoption will be the recognition, on a discounted basis, of our minimum commitments under noncancelable operating leases as right of use assets and liabilities on our Consolidated Balance Sheets. This will result in a significant increase in assets and liabilities recorded on our Consolidated Balance Sheets. Although we expect the new lease guidance will have a material impact on our Consolidated Balance Sheets, we are continuing to evaluate the practical expedient guidance provisions available and the extent of potential impacts on our consolidated financial statements, processes and internal controls.