Summary of Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2012
Accounting Policies [Abstract]
Cash Equivalents	Cash Equivalents Cash equivalents included investments in money market funds totaling $1.2 billion and $1.3 billion at March 31, 2012 and December 31, 2011, respectively. Generally, the carrying value of cash equivalents equals the fair value, as these investments have maturities of three months or less. Edison International temporarily invests the ending daily cash balance in its primary disbursement accounts until required for check clearing. Edison International reclassified $178 million and $220 million of checks issued, but not yet paid by the financial institution, from cash to accounts payable at March 31, 2012 and December 31, 2011, respectively.
Restricted Cash and Cash Equivalents	Restricted Cash and Cash Equivalents Restricted cash and cash equivalents at March 31, 2012 and December 31, 2011 included $97 million received from a wind financing that was held in escrow at those dates and is expected to be released in the second quarter of 2012 when the project achieves certain completion milestones. At March 31, 2012, restricted cash and cash equivalents also included $74 million to support outstanding letters of credit issued under EMG's letter of credit facilities. Inventory Inven
Inventory	Inventory Inventory is stated at the lower of cost or market, cost being determined by the weighted-average cost method for fuel, and the average cost method for materials and supplies.
Earnings Per Share	Earnings Per Share Edison International computes earnings per share ("EPS") using the two-class method, which is an earnings allocation formula that determines EPS for each class of common stock and participating security. Edison International's participating securities are stock-based compensation awards payable in common shares, including stock options, performance shares and restricted stock units, which earn dividend equivalents on an equal basis with common shares. Stock options awarded during the period 2003 through 2006 received dividend equivalents.

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2012

Cash equivalents included investments in money market funds totaling $1.2 billion and $1.3 billion at March 31, 2012 and December 31, 2011, respectively. Generally, the carrying value of cash equivalents equals the fair value, as these investments have maturities of three months or less.

Edison International temporarily invests the ending daily cash balance in its primary disbursement accounts until required for check clearing. Edison International reclassified $178 million and $220 million of checks issued, but not yet paid by the financial institution, from cash to accounts payable at March 31, 2012 and December 31, 2011, respectively.

Restricted Cash and Cash Equivalents

Restricted cash and cash equivalents at March 31, 2012 and December 31, 2011 included $97 million received from a wind financing that was held in escrow at those dates and is expected to be released in the second quarter of 2012 when the project achieves certain completion milestones. At March 31, 2012, restricted cash and cash equivalents also included $74 million to support outstanding letters of credit issued under EMG's letter of credit facilities.

Inventory

Inven

Inventory

Inventory is stated at the lower of cost or market, cost being determined by the weighted-average cost method for fuel, and the average cost method for materials and supplies.

Earnings Per Share

Edison International computes earnings per share ("EPS") using the two-class method, which is an earnings allocation formula that determines EPS for each class of common stock and participating security. Edison International's participating securities are stock-based compensation awards payable in common shares, including stock options, performance shares and restricted stock units, which earn dividend equivalents on an equal basis with common shares. Stock options awarded during the period 2003 through 2006 received dividend equivalents.

- Definition

Disclosure of accounting policy for cash and cash equivalents with respect to unrestricted balances.

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- Definition

Disclosure of accounting policy for computing basic and diluted earnings or loss per share for each class of common stock and participating security. Addresses all significant policy factors, including any antidilutive items that have been excluded from the computation and takes into account stock dividends, splits and reverse splits that occur after the balance sheet date of the latest reporting period but before the issuance of the financial statements.

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- Definition

Disclosure of accounting policy for major classes of inventories, bases of stating inventories (for example, lower of cost or market), methods by which amounts are added and removed from inventory classes (for example, FIFO, LIFO, or average cost), loss recognition on impairment of inventories, and situations in which inventories are stated above cost. If inventory is carried at cost, this disclosure includes the nature of the cost elements included in inventory.

+ References

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+ Details