Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Movement in Valuation and Qualifying Accounts
Balance at Beginning of Period	$ 61.7	$ 72.2	$ 70.0
Charged to Costs and Expenses	33.6	41.9	43.8
Charged to Other Accounts	0.0	0.0	0.0
Deductions	33.5	52.4	41.6
Balance at End of Period	61.8	61.7	72.2
Deferred tax assets, loss and credit carryforwards	1,418.0	1,388.0		$ 2,200.0
Customers
Movement in Valuation and Qualifying Accounts
Balance at Beginning of Period	46.2	48.9	52.2
Charged to Costs and Expenses	17.7	23.9	24.1
Charged to Other Accounts	0.0	0.0	0.0
Deductions	22.7	26.6	27.4
Balance at End of Period	41.2	46.2	48.9
All others
Movement in Valuation and Qualifying Accounts
Balance at Beginning of Period	15.5	23.3	17.8
Charged to Costs and Expenses	15.9	18.0	19.7
Charged to Other Accounts	0.0	0.0	0.0
Deductions	10.8	25.8	14.2
Balance at End of Period	20.6	15.5	23.3
Tax valuation allowance
Movement in Valuation and Qualifying Accounts
Balance at Beginning of Period	32.0	29.0	1,380.0
Charged to Costs and Expenses	0.0	3.0	0.0
Charged to Other Accounts	0.0	0.0	0.0
Deductions	8.0	0.0	1,351.0
Balance at End of Period	24.0	32.0	29.0
Edison Mission Energy
Movement in Valuation and Qualifying Accounts
Deferred tax assets, loss and credit carryforwards				1,600.0
Deferred income tax benefits, net				$ 220.0
Southern California Edison Company
Movement in Valuation and Qualifying Accounts
Balance at Beginning of Period	61.7	67.6	65.5
Charged to Costs and Expenses	32.9	41.9	43.7
Charged to Other Accounts	0.0	0.0	0.0
Deductions	33.5	47.8	41.6
Balance at End of Period	61.1	61.7	67.6
Deferred tax assets, loss and credit carryforwards	0.0	0.0
Southern California Edison Company | Customers
Movement in Valuation and Qualifying Accounts
Balance at Beginning of Period	46.2	48.9	52.2
Charged to Costs and Expenses	17.0	23.9	24.1
Charged to Other Accounts	0.0	0.0	0.0
Deductions	22.7	26.6	27.4
Balance at End of Period	40.5	46.2	48.9
Southern California Edison Company | All others
Movement in Valuation and Qualifying Accounts
Balance at Beginning of Period	15.5	18.7	13.3
Charged to Costs and Expenses	15.9	18.0	19.6
Charged to Other Accounts	0.0	0.0	0.0
Deductions	10.8	21.2	14.2
Balance at End of Period	$ 20.6	$ 15.5	$ 18.7