Contingencies And Commitments (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Transportation Equipment [Member]
Transportation equipment lease expiration period	7 years
Guarantees Residual Value, Fair Value Disclosure	$ 1.4
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 7.9
Transportation Equipment [Member] | Ferrellgas, L.P. [Member]
Transportation equipment lease expiration period	7 years
Guarantees Residual Value, Fair Value Disclosure	$ 1.4
Guarantor Obligations, Maximum Exposure, Undiscounted	7.9
Property And Equipment [Member]
Rental expense	50.0	$ 49.2	$ 45.0
Property And Equipment [Member] | Ferrellgas, L.P. [Member]
Rental expense	$ 50.0	$ 49.2	$ 45.0