Business combinations Business combinations (Narrative) (Details) - Midstream - Crude Oil Logistics [Member]
$ in Millions
6 Months Ended
Jan. 31, 2016
USD ($)
Payments to Acquire Businesses, Gross $ 560.0
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable 260.0
Business Acquisition Cost Of Acquired Entity Issuance Of Liabilities And Other Costs 2.5
Business Combination, Consideration Transferred 822.5
Ferrellgas, L.P. [Member]  
Payments to Acquire Businesses, Gross 560.0
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable 260.0
Business Acquisition Cost Of Acquired Entity Issuance Of Liabilities And Other Costs 2.5
Business Combination, Consideration Transferred $ 822.5