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Other Investments (Amortized Cost and Fair Value of Nuclear Decommissioning Trusts) (Details) - USD ($) $ in Millions | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Nuclear Decommissioning Trusts Disclosures |  |  |  |  |
Fair Value |  | $ 4,331 | $ 4,799 |  |
Southern California Edison |  |  |  |  |
Nuclear Decommissioning Trusts Disclosures |  |  |  |  |
Amortized Cost |  | 2,917 | 3,020 |  |
Fair Value |  | 4,331 | 4,799 | $ 4,494 | $ 4,048
Southern California Edison | Stocks |  |  |  |  |
Nuclear Decommissioning Trusts Disclosures |  |  |  |  |
Amortized Cost |  | 304 | 524 |  |
Fair Value |  | $ 1,460 | 2,031 |  |
Southern California Edison | Municipal bonds |  |  |  |  |
Nuclear Decommissioning Trusts Disclosures |  |  |  |  |
Longest Maturity Dates (in years) |  | 2054 |  |  |
Amortized Cost |  | $ 691 | 681 |  |
Fair Value |  | $ 840 | 822 |  |
Southern California Edison | U.S. government and agency securities |  |  |  |  |
Nuclear Decommissioning Trusts Disclosures |  |  |  |  |
Longest Maturity Dates (in years) |  | 2046 |  |  |
Amortized Cost |  | $ 1,070 | 777 |  |
Fair Value |  | $ 1,128 | 836 |  |
Southern California Edison | Corporate bonds |  |  |  |  |
Nuclear Decommissioning Trusts Disclosures |  |  |  |  |
Longest Maturity Dates (in years) |  | 2057 |  |  |
Amortized Cost |  | $ 708 | 346 |  |
Fair Value |  | $ 755 | 395 |  |
Southern California Edison | Short-term investments and receivables/payables |  |  |  |  |
Nuclear Decommissioning Trusts Disclosures |  |  |  |  |
Longest Maturity Dates (in years) | [1] | One-year |  |  |
Amortized Cost | [1] | $ 144 | 692 |  |
Fair Value | [1] | $ 148 | $ 715 |  |
[1] | Short-term investments include $81 million and $164 million of repurchase agreements payable by financial institutions which earn interest, are fully secured by U.S. Treasury securities and mature by January 5, 2016 and January 7, 2015 as of December 31, 2015 and 2014, respectively.

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- Definition The amount of decommissioning trust assets at amortized cost as of the balance sheet date. + References No definition available. + Details
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- Definition The maturity dates for decommissioning trust investments. + References No definition available. + Details
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- Definition The fair value of investments held in a trust fund to pay for the costs of decontaminating and decommissioning facilities, whether such amount is presented as a separate caption or as a parenthetical disclosure on the balance sheet. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
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