Derivative Instruments and Hedging Activities (Narrative) (Details) MMBbls in Millions	12 Months Ended
Jul. 31, 2017 USD ($) MMBbls	Jul. 31, 2016 USD ($)
Derivative [Line Items]
gain or loss in earnings related to hedge ineffectiveness	$ 0
Reclassification of net gain to earnings during next 12 months	10,700,000
Reclassification of gain (loss) to earnings from discontinuance of cash flow hedges	0	$ 0
Derivative amount of credit risk	15,000,000
Derivative, Net Liability Position, Aggregate Fair Value	0
Collateral Already Posted, Aggregate Fair Value	0
Additional Collateral, Aggregate Fair Value	0
Ferrellgas, L.P. [Member]
Derivative [Line Items]
gain or loss in earnings related to hedge ineffectiveness	0
Reclassification of net gain to earnings during next 12 months	(10,700,000)
Reclassification of gain (loss) to earnings from discontinuance of cash flow hedges	$ 0	$ 0
Number of barrels of propane covered by cash flow hedges \| MMBbls	3.3
Derivative amount of credit risk	$ 15,000,000
Derivative, Net Liability Position, Aggregate Fair Value	0
Collateral Already Posted, Aggregate Fair Value	0
Additional Collateral, Aggregate Fair Value	$ 0
Propane [Member]
Derivative [Line Items]
Number of barrels of propane covered by cash flow hedges \| MMBbls	3.3
Crude Oil [Member]
Derivative [Line Items]
Number of barrels of propane covered by cash flow hedges \| MMBbls	0.2
Crude Oil [Member] \| Ferrellgas, L.P. [Member]
Derivative [Line Items]
Number of barrels of propane covered by cash flow hedges \| MMBbls	0.2

Derivative amount of credit risk if counterparties failed to perform contracts

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- Definition

The aggregate fair value of additional assets that would be required to be posted as collateral for derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4H
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624258-113959

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The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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- Definition

The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4H
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624258-113959

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4H
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624258-113959

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- Definition

Nominal volume used to calculate payments on a derivative instrument.

+ References

No definition available.

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- Definition

The net gain (loss) recognized in earnings during the reporting period representing the amount of the cash flow hedges' ineffectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

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- Definition

The amount of net gain (loss) reclassified into earnings in the period when cash flow hedge is discontinued because it is probable that the original forecasted transactions will not occur by the end of the original period or an additional two month time period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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