Benefit Plans (Schedule Of Components Of Net Periodic Benefit Cost (Income)) (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2016 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
|
| Pension [Member] | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Service cost | $ 18 | $ 22 | $ 55 | $ 65 |
| Interest cost | 70 | 84 | 211 | 252 |
| Expected return on plan assets | (139) | (135) | (416) | (405) |
| Amortization of net loss | 43 | 58 | 130 | 175 |
| Amortization of prior service cost (credit) | 2 | 2 | 4 | 6 |
| Termination and curtailment | 0 | 0 | 20 | 0 |
| Net periodic benefit cost (income) | (6) | 31 | 4 | 93 |
| Postretirement [Member] | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Service cost | 4 | 4 | 12 | 13 |
| Interest cost | 18 | 24 | 58 | 75 |
| Expected return on plan assets | 0 | 0 | 0 | 0 |
| Amortization of net loss | 3 | 10 | 19 | 33 |
| Amortization of prior service cost (credit) | (10) | (10) | (29) | (30) |
| Termination and curtailment | 0 | 0 | 0 | 0 |
| Net periodic benefit cost (income) | $ 15 | $ 28 | $ 60 | $ 91 |