Fair Value Measurements - Other Financial Instruments (Details) - USD ($) $ in Millions	Oct. 31, 2019	Jul. 31, 2019
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value	$ 1,735.5	$ 1,824.6
Level 2 [Member] | Ferrellgas, L.P. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value	1,514.2	$ 1,562.2
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes receivable, fair value	13.3
Notes receivable, carrying amount in excess of fair value	0.5
Fair Value, Inputs, Level 3 [Member] | Ferrellgas, L.P. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes receivable, fair value	13.3
Notes receivable, carrying amount in excess of fair value	$ 0.5