Document And Entity Information - USD ($)	12 Months Ended
	Jul. 31, 2020	Aug. 31, 2020	Jan. 31, 2020
Document Information [Line Items]
Document Type	10-K
Document Period End Date	Jul. 31, 2020
Entity Registrant Name	Ferrellgas Partners L P
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	Yes
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		97,152,665
Entity Public Float			$ 24,544,217
Current Fiscal Year End Date	--07-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0000922358
Amendment Flag	false
Ferrellgas Partners Finance Corp. [Member]
Document Information [Line Items]
Document Type	10-K
Document Period End Date	Jul. 31, 2020
Entity Registrant Name	FERRELLGAS PARTNERS FINANCE CORP
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	Yes
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	true
Current Fiscal Year End Date	--07-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0001012493
Amendment Flag	false
Ferrellgas, L.P. [Member]
Document Information [Line Items]
Document Type	10-K
Document Period End Date	Jul. 31, 2020
Entity Registrant Name	FERRELLGAS L P
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	Yes
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Current Fiscal Year End Date	--07-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0000922359
Amendment Flag	false
Ferrellgas Finance Corp. [Member]
Document Information [Line Items]
Document Type	10-K
Document Period End Date	Jul. 31, 2020
Entity Registrant Name	FERRELLGAS FINANCE CORP
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	Yes
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	true
Current Fiscal Year End Date	--07-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0000922360
Amendment Flag	false