Compensation and Benefit Plans (Pension Plan Assets - Fair Value Levels) (Details) (Pension Plans, USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	$ 3,459		$ 3,558
Receivables and payables, net	(5)		(81)
Fair Value of Plan Assets	3,454		3,477		3,542
Level 1
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	984		978
Level 2
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	2,186		2,190
Level 3
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	289		390
Fair Value of Plan Assets	289		390		414
U.S. government and agency securities
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	469	[1]	666	[1]
U.S. government and agency securities | Level 1
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	140	[1]	195	[1]
U.S. government and agency securities | Level 2
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	329	[1]	471	[1]
U.S. government and agency securities | Level 3
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	0	[1]	0	[1]
Corporate stocks
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	730	[2]	653	[2]
Corporate stocks | Level 1
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	716	[2]	653	[2]
Corporate stocks | Level 2
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	14	[2]	0	[2]
Corporate stocks | Level 3
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	0	[2]	0	[2]
Corporate bonds
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	801	[3]	553	[3]
Corporate bonds | Level 1
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	0	[3]	0	[3]
Corporate bonds | Level 2
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	801	[3]	553	[3]
Corporate bonds | Level 3
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	0	[3]	0	[3]
Common/collective funds
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	524	[4]	546	[4]
Common/collective funds | Level 1
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	0	[4]	0	[4]
Common/collective funds | Level 2
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	524	[4]	546	[4]
Common/collective funds | Level 3
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	0	[4]	0	[4]
Partnerships/joint ventures
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	399	[5]	538	[5]
Partnerships/joint ventures | Level 1
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	0	[5]	0	[5]
Partnerships/joint ventures | Level 2
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	110	[5]	148	[5]
Partnerships/joint ventures | Level 3
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	289	[5]	390	[5]
Other investment entities
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	278	[6]	282	[6]
Other investment entities | Level 1
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	0	[6]	0	[6]
Other investment entities | Level 2
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	278	[6]	282	[6]
Other investment entities | Level 3
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	0	[6]	0	[6]
Registered investment companies
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	143	[7]	193	[7]
Registered investment companies | Level 1
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	113	[7]	112	[7]
Registered investment companies | Level 2
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	30	[7]	81	[7]
Registered investment companies | Level 3
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	0	[7]	0	[7]
Interest-bearing cash
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	10		12
Interest-bearing cash | Level 1
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	10		12
Interest-bearing cash | Level 2
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	0		0
Interest-bearing cash | Level 3
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	0		0
Other
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	105		115
Other | Level 1
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	5		6
Other | Level 2
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	100		109
Other | Level 3
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	0		0
Asset backed securities including distressed mortgages | Level 3
Pension and Other Postretirement Benefits
Actual plan asset allocations	55.00%		64.00%
Non-index fund
Pension and Other Postretirement Benefits
Performance percentage benchmark	27.00%		23.00%
Global asset allocation fund
Pension and Other Postretirement Benefits
Actual plan asset allocations	3.00%		6.00%
Collateralized mortgage obligations and other asset backed securities
Pension and Other Postretirement Benefits
Fair Value of Plan Assets, Gross	102		78
Defined Benefit Plan, Fair Value of Plan Assets below Investment Grade	15		15
Russell 200 and Russell 1000 indexes | Corporate stocks
Pension and Other Postretirement Benefits
Performance percentage benchmark	59.00%		51.00%
Russell 200 and Russell 1000 indexes | Undervalued Securities
Pension and Other Postretirement Benefits
Performance percentage benchmark	18.00%		28.00%
Morgan Stanley Capital International | Corporate stocks
Pension and Other Postretirement Benefits
Performance percentage benchmark	41.00%		49.00%
Standard And Poors 500 Index | Equity index fund
Pension and Other Postretirement Benefits
Performance percentage benchmark	32.00%		27.00%
Morgan Stanley Capital International Europe Australasia And Far East Index | Equity index fund
Pension and Other Postretirement Benefits
Performance percentage benchmark	20.00%		15.00%
Southern California Edison
Pension and Other Postretirement Benefits
Fair Value of Plan Assets	$ 3,217		$ 3,236		$ 3,320

[1] Level 1 U.S. government and agency securities are U.S. treasury bonds and notes. Level 2 primarily relates to the Federal National Mortgage Association and the Federal Home Loan Mortgage Corporation.

[2] Corporate stocks are diversified. For 2014 and 2013, respectively, performance is primarily benchmarked against the Russell Indexes (59% and 51%) and Morgan Stanley Capital International (MSCI) index (41% and 49%).

[3] Corporate bonds are diversified. At December 31, 2014 and 2013, respectively, this category includes $102 million and $78 million for collateralized mortgage obligations and other asset backed securities of which $15 million and $15 million are below investment grade.

[4] At December 31, 2014 and 2013, respectively, the common/collective assets were invested in equity index funds that seek to track performance of the Standard and Poor's (S&P 500) Index (32% and 27%), Russell 1000 indexes (18% and 28%) and the MSCI Europe, Australasia and Far East (EAFE) Index (20% and 15%). A non-index U.S. equity fund representing 27% and 23% of this category for 2014 and 2013, respectively, is actively managed. Another fund representing 3% and 6% of this category for 2014 and 2013, respectively, is a global asset allocation fund

[5] Partnerships/joint venture Level 2 investments consist primarily of a partnership which invests in publicly traded fixed income securities, primarily from the banking and finance industry and U.S. government agencies. At December 31, 2014 and 2013, respectively, approximately 55% and 64% of the Level 3 partnerships are invested in (1) asset backed securities, including distressed mortgages and (2) commercial and residential loans and debt and equity of banks. The remaining Level 3 partnerships are invested in small private equity and venture capital funds. Investment strategies for these funds include branded consumer products, early stage technology, California geographic focus, and diversified US and non-US fund-of-funds.

[6] Other investment entities were primarily invested in (1) emerging market equity securities, (2) a hedge fund that invests through liquid instruments in a global diversified portfolio of equity, fixed income, interest rate, foreign currency and commodities markets, and (3) domestic mortgage backed securitie

[7] Level 1 of registered investment companies primarily consisted of a global equity mutual fund which seeks to outperform the MSCI World Total Return Index. Level 2 primarily consisted of a short-term bond fund.