Accounts And Notes Receivable, Net And Accounts Receivable Securitization (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 31, 2011	Jul. 31, 2010
Proceeds to Ferrellgas from securitizing receivables to a commercial paper conduit	$ 61.0	$ 47.0
Available proceeds from additional trade accounts receivable	3.0	11.0
Ferrellgas, L.P. And Subsidiaries [Member] | Maximum [Member]
Proceeds to Ferrellgas from securitizing receivables to a commercial paper conduit	145.0
Maximum [Member]
Proceeds to Ferrellgas from securitizing receivables to a commercial paper conduit	145.0
Ferrellgas, L.P. And Subsidiaries [Member] | Accounts Receivable Securitization [Member]
Weighted average discount rate to value the retained interest in the transferred receivables	3.60%	3.50%
Accounts Receivable Securitization [Member]
Weighted average discount rate to value the retained interest in the transferred receivables	3.60%	3.50%
Ferrellgas, L.P. And Subsidiaries [Member] | Commercial Paper [Member]
Pledged trade receivable as collateral against collateralized notes payable	112.5
Note payable to Ferrellgas, L.P.	61.0
Commercial Paper [Member]
Pledged trade receivable as collateral against collateralized notes payable	112.5
Note payable to Ferrellgas, L.P.	61.0
Ferrellgas, L.P. And Subsidiaries [Member]
Proceeds to Ferrellgas from securitizing receivables to a commercial paper conduit	61.0	47.0
Available proceeds from additional trade accounts receivable	$ 3.0	$ 11.0