Debt (Secured Credit Facility Narrative) (Details) (Secured Credit Facility [Member], USD $) In Millions, unless otherwise specified	Oct. 31, 2012	Jul. 31, 2012
Total borrowings outstanding, line of credit facility	$ 193.5	$ 160.0
Amount classified as long-term debt	75.6	64.3
Weighted average interest rate of debt	4.10%	4.20%
Ferrellgas, L.P. [Member]
Total borrowings outstanding, line of credit facility	193.5	160.0
Amount classified as long-term debt	75.6	64.3
Weighted average interest rate of debt	4.10%	4.20%
Letter Of Credit [Member]
Letters of credit outstanding	55.6	64.5
Letter of credit facility, remaining capacity	144.4	135.5
Letter Of Credit [Member] | Ferrellgas, L.P. [Member]
Letters of credit outstanding	55.6	64.5
Letter of credit facility, remaining capacity	$ 144.4	$ 135.5