Pension And OPEB (Schedule Of Pension And OPEB Costs) (Detail) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Pension Benefits [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Total Benefit Costs | $ (9) | $ 1 |
| Pension Benefits [Member] | PSE And G [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Total Benefit Costs | (8) | (1) |
| Pension Benefits [Member] | Power [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Total Benefit Costs | (2) | 0 |
| Pension Benefits [Member] | Other Entity [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Total Benefit Costs | 1 | 2 |
| OPEB [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Total Benefit Costs | 26 | 22 |
| OPEB [Member] | PSE And G [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Total Benefit Costs | 17 | 14 |
| OPEB [Member] | Power [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Total Benefit Costs | 8 | 7 |
| OPEB [Member] | Other Entity [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Total Benefit Costs | $ 1 | $ 1 |