Debt Debt (Components of Long-Term Debt) (Details) - Secured Debt [Member] - USD ($) $ in Millions	May 04, 2018	Apr. 30, 2018
Two Thousand and Twenty Three Credit Facility [Member] | Subsequent Event [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 575.0
Two Thousand and Eighteen Credit Facility [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 575.0
Ferrellgas, L.P. [Member] | Two Thousand and Twenty Three Credit Facility [Member] | Subsequent Event [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 575.0
Ferrellgas, L.P. [Member] | Two Thousand and Eighteen Credit Facility [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 575.0