Derivative Financial Instruments (Schedule Of NYMEX Contracts And Butane Price Swap Purchase Agreements) (Details) bbl in Millions |
Jun. 30, 2019
bbl
|
|---|---|
| Economic Hedges [Member] | |
| Derivative [Line Items] | |
| Derivative, Nonmonetary Notional Amount | 4.3 |
| Economic Hedges Futures [Member] | |
| Derivative [Line Items] | |
| Derivative, Nonmonetary Notional Amount | 1.3 |