Debt and Credit Agreements (Long-term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Current portion of long-term debt	$ (481)	$ (981)
Long-term debt	11,642	10,175
Edison International Parent and Other
Debt Instrument [Line Items]
Other long-term debt	29	32
Current portion of long-term debt	(2)	(402)
Unamortized debt discount and issuance costs, net	(13)	(9)
Long-term debt	1,214	421
Edison International Parent and Other \| Debentures and notes
Debt Instrument [Line Items]
Long-term debt	$ 1,200	800
Edison International Parent and Other \| Debentures and notes \| Minimum
Debt Instrument [Line Items]
Interest rate on debt (as a percent)	2.125%
Edison International Parent and Other \| Debentures and notes \| Maximum
Debt Instrument [Line Items]
Interest rate on debt (as a percent)	2.95%
SCE
Debt Instrument [Line Items]
Current portion of long-term debt	$ (479)	(579)
Unamortized debt discount and issuance costs, net	(88)	(105)
Long-term debt	10,428	9,754
SCE \| Debentures and notes
Debt Instrument [Line Items]
Long-term debt	$ 307	307
SCE \| Debentures and notes \| Minimum
Debt Instrument [Line Items]
Interest rate on debt (as a percent)	5.06%
SCE \| Debentures and notes \| Maximum
Debt Instrument [Line Items]
Interest rate on debt (as a percent)	6.65%
SCE \| First and refunding mortgage bonds
Debt Instrument [Line Items]
Long-term debt	$ 9,779	9,357
SCE \| First and refunding mortgage bonds \| Minimum
Debt Instrument [Line Items]
Interest rate on debt (as a percent)	1.845%
SCE \| First and refunding mortgage bonds \| Maximum
Debt Instrument [Line Items]
Interest rate on debt (as a percent)	6.05%
SCE \| Pollution-control bonds
Debt Instrument [Line Items]
Long-term debt	$ 909	$ 774
SCE \| Pollution-control bonds \| Minimum
Debt Instrument [Line Items]
Interest rate on debt (as a percent)	1.375%
SCE \| Pollution-control bonds \| Maximum
Debt Instrument [Line Items]
Interest rate on debt (as a percent)	5.00%

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of unamortized debt discount (premium) and debt issuance costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of long-term debt classified as other.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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