Segment Information - Total Contract Revenue (Detail) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Oncor | |||
| Revenues from External Customers and Long-Lived Assets [Line Items] | |||
| Total contract revenue | 17.90% | 10.30% | 14.80% |
| Enterprise Products Partners L.P. | |||
| Revenues from External Customers and Long-Lived Assets [Line Items] | |||
| Total contract revenue | 12.50% | 9.10% | 11.90% |