Balance Sheet Components Investments Held in Trust (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Marketable securities, at fair value:
Decommissioning Fund Investments, Fair Value	$ 82	$ 38
Non-qualified benefit plan trust	35	32
Nuclear Decommissioning [Member]
Cash equivalents	59	15
Marketable securities, at fair value:
Equity securities	0	0
Debt securities	23	23
Insurance contracts, at cash surrender value	0	0
Decommissioning Fund Investments, Fair Value	82	38
Non Qualified Benefit Plans [Member]
Cash equivalents	0	2
Marketable securities, at fair value:
Equity securities	8	5
Debt securities	1	2
Insurance contracts, at cash surrender value	26	23
Non-qualified benefit plan trust	$ 35	$ 32