Derivative Instruments and Hedging Activities (Narrative) (Details) MMBbls in Millions	9 Months Ended
Apr. 30, 2018 USD ($) MMBbls	Apr. 30, 2017 USD ($)
Reclassification of net gain to earnings during next 12 months	$ 12,200,000
Description of Reclassification of Cash Flow Hedge Gain (Loss)	0
Number of barrels of propane covered by cash flow hedges \| MMBbls	2.3
Derivative amount of credit risk	$ 5,700,000
Derivative net liability position aggregate fair value	0
Gain or loss in earnings related to hedge ineffectiveness	0	$ 0
Reclassifications to earnings resulting from discontinuance of cash flow hedges	0	0
Ferrellgas, L.P. [Member]
Reclassification of net gain to earnings during next 12 months	$ 12,200,000
Description of Reclassification of Cash Flow Hedge Gain (Loss)	0
Number of barrels of propane covered by cash flow hedges \| MMBbls	2.3
Derivative amount of credit risk	$ 5,700,000
Derivative net liability position aggregate fair value	0
Gain or loss in earnings related to hedge ineffectiveness	0	0
Reclassifications to earnings resulting from discontinuance of cash flow hedges	$ 0	$ 0

Derivative amount of credit risk if counterparties failed to perform contracts

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- Definition

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 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.

+ Details

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- Definition

Description of the transactions or other events that will result in the reclassification into earnings of gains or losses reported in accumulated other comprehensive income. May include the time period over which gains or losses will be reclassified to earnings.

+ 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 (b)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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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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