Equity Method Investments (Schedule Of Equity Method Investments) (Details) - LLC Membership |
Dec. 31, 2015 |
|---|---|
| Hardy Storage Company, L.L.C. | |
| Schedule of Equity Method Investments [Line Items] | |
| Percentage of voting power held | 49.00% |
| Pennant Midstream, L.L.C. | |
| Schedule of Equity Method Investments [Line Items] | |
| Percentage of voting power held | 47.50% |
| Millennium Pipeline Company, L.L.C | |
| Schedule of Equity Method Investments [Line Items] | |
| Percentage of voting power held | 47.50% |