Variable Interest Entities (Textual) (Details) - Southern California Edison - Variable Interest Entity, Not Primary Beneficiary	3 Months Ended
	Mar. 31, 2017 USD ($) $ / shares MW	Mar. 31, 2016 USD ($)	Dec. 31, 2016 MW
SCE Power Purchase Contracts
Variable Interest Entity
Power generating capacity (in megawatts) | MW	4,928		4,383
Payments to unconsolidated VIEs for power purchase contracts	$ 140,000,000	$ 127,000,000
Trust I
Variable Interest Entity
Common stock	$ 10,000
Trust I | Trust Securities
Variable Interest Entity
Security dividend rate, (as a percent)	5.625%
Liquidation preference	$ 475,000,000
Liquidation value (in dollars per share) | $ / shares	$ 25
Common stock	$ 10,000
Trust I | Series F Preferred Stock
Variable Interest Entity
Security dividend rate, (as a percent)	5.625%
Liquidation preference	$ 475,000,000
Liquidation value (in dollars per share) | $ / shares	$ 2,500
Trust II
Variable Interest Entity
Common stock	$ 10,000
Trust II | Trust Securities
Variable Interest Entity
Security dividend rate, (as a percent)	5.10%
Liquidation preference	$ 400,000,000
Liquidation value (in dollars per share) | $ / shares	$ 25
Trust II | Series G Preferred Stock
Variable Interest Entity
Security dividend rate, (as a percent)	5.10%
Liquidation preference	$ 400,000,000
Liquidation value (in dollars per share) | $ / shares	$ 2,500
Trust III
Variable Interest Entity
Common stock	$ 10,000
Trust III | Trust Securities
Variable Interest Entity
Security dividend rate, (as a percent)	5.75%
Liquidation preference	$ 275,000,000
Liquidation value (in dollars per share) | $ / shares	$ 25
Trust III | Series H Preferred Stock
Variable Interest Entity
Security dividend rate, (as a percent)	5.75%
Liquidation preference	$ 275,000,000
Liquidation value (in dollars per share) | $ / shares	$ 2,500
Trust IV
Variable Interest Entity
Common stock	$ 10,000
Trust IV | Trust Securities
Variable Interest Entity
Security dividend rate, (as a percent)	5.375%
Liquidation preference	$ 325,000,000
Liquidation value (in dollars per share) | $ / shares	$ 25
Trust IV | Series J Preferred Stock
Variable Interest Entity
Security dividend rate, (as a percent)	5.375%
Liquidation preference	$ 325,000,000
Liquidation value (in dollars per share) | $ / shares	$ 2,500
Trust IV | Series K Preferred Stock
Variable Interest Entity
Liquidation preference	$ 300,000,000
Trust V
Variable Interest Entity
Common stock	$ 10,000
Trust V | Trust Securities
Variable Interest Entity
Security dividend rate, (as a percent)	5.45%
Liquidation preference	$ 300,000,000
Liquidation value (in dollars per share) | $ / shares	$ 25
Trust V | Series K Preferred Stock
Variable Interest Entity
Security dividend rate, (as a percent)	5.45%
Liquidation preference	$ 300,000,000
Liquidation value (in dollars per share) | $ / shares	$ 2,500