v3.8.0.1

SAN ONOFRE NUCLEAR GENERATING STATION (Tables) | 3 Months Ended
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Mar. 31, 2018
Public Utilities, General Disclosures [Abstract] |
Schedule of Nuclear Decommissioning Trusts Investments | The following table shows the fair values and gross unrealized gains and losses for the securities held in the NDT. We provide additional fair value disclosures for the NDT in Note 9.
NUCLEAR DECOMMISSIONING TRUSTS
(Dollars in millions)
| Cost |  | Gross unrealized gains |  | Gross unrealized losses |  | Estimated fair value
At March 31, 2018: |  |  |  |  |  |  |
Debt securities: |  |  |  |  |  |  |
Debt securities issued by the U.S. Treasury and other |  |  |  |  |  |  |
U.S. government corporations and agencies(1) | $ | 44 |  |  | $ | — |  |  | $ | — |  |  | $ | 44 |
Municipal bonds(1) | 245 |  |  | 4 |  |  | (2 | ) |  | 247 |
Other securities(2) | 217 |  |  | 2 |  |  | (3 | ) |  | 216 |
Total debt securities | 506 |  |  | 6 |  |  | (5 | ) |  | 507 |
Equity securities | 172 |  |  | 321 |  |  | (2 | ) |  | 491 |
Cash and cash equivalents | 19 |  |  | — |  |  | — |  |  | 19 |
Total | $ | 697 |  |  | $ | 327 |  |  | $ | (7 | ) |  | $ | 1,017 |
At December 31, 2017: |  |  |  |  |  |  |
Debt securities: |  |  |  |  |  |  |
Debt securities issued by the U.S. Treasury and other |  |  |  |  |  |  |
U.S. government corporations and agencies | $ | 54 |  |  | $ | — |  |  | $ | — |  |  | $ | 54 |
Municipal bonds | 245 |  |  | 7 |  |  | (2 | ) |  | 250 |
Other securities | 215 |  |  | 3 |  |  | (1 | ) |  | 217 |
Total debt securities | 514 |  |  | 10 |  |  | (3 | ) |  | 521 |
Equity securities | 171 |  |  | 326 |  |  | (1 | ) |  | 496 |
Cash and cash equivalents | 16 |  |  | — |  |  | — |  |  | 16 |
Total | $ | 701 |  |  | $ | 336 |  |  | $ | (4 | ) |  | $ | 1,033 |
(1) | Maturity dates are 2018-2048.
(2) | Maturity dates are 2018-2064.
Schedule of Sales of Securities By Nuclear Decommissioning Trusts | The following table shows the proceeds from sales of securities in the NDT and gross realized gains and losses on those sales:
SALES OF SECURITIES IN THE NDT
(Dollars in millions)
| Three months ended March 31,
| 2018 |  | 2017
Proceeds from sales(1) | $ | 210 |  |  | $ | 357 |
Gross realized gains | 4 |  |  | 45 |
Gross realized losses | (3 | ) |  | (5 | )
(1) Excludes securities that are held to maturity.

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