Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Movement in Valuation and Qualifying Accounts
Balance at Beginning of Period	$ 49.7	$ 51.5	$ 53.9
Charged to Costs and Expenses	45.3	32.2	35.2
Charged to Other Accounts	120.0	0.0	0.0
Deductions	27.1	34.0	37.6
Balance at End of Period	187.9	49.7	51.5
Recorded valuation allowance	31.0
Capital loss from sale of SoCore Energy
Movement in Valuation and Qualifying Accounts
Recorded valuation allowance	4.0		4.0
Customers
Movement in Valuation and Qualifying Accounts
Balance at Beginning of Period	35.8	32.0	36.6
Charged to Costs and Expenses	35.9	22.2	19.0
Charged to Other Accounts	120.0	0.0	0.0
Deductions	16.3	18.4	23.6
Balance at End of Period	175.4	35.8	32.0
All others
Movement in Valuation and Qualifying Accounts
Balance at Beginning of Period	13.9	19.5	17.3
Charged to Costs and Expenses	9.4	10.0	16.2
Charged to Other Accounts	0.0	0.0	0.0
Deductions	10.8	15.6	14.0
Balance at End of Period	12.5	13.9	19.5
Tax valuation allowance
Movement in Valuation and Qualifying Accounts
Balance at Beginning of Period	35.0	36.0	28.0
Charged to Costs and Expenses	0.0	0.0	0.0
Charged to Other Accounts	0.0	0.0	8.0
Deductions	0.0	1.0	0.0
Balance at End of Period	35.0	35.0	36.0
Tax valuation allowance | Non-California state
Movement in Valuation and Qualifying Accounts
Charged to Other Accounts			4.0
SCE
Movement in Valuation and Qualifying Accounts
Balance at Beginning of Period	49.4	51.1	53.3
Charged to Costs and Expenses	45.0	32.0	35.1
Charged to Other Accounts	120.0	0.0	0.0
Deductions	26.7	33.7	37.3
Balance at End of Period	187.7	49.4	51.1
SCE | Customers
Movement in Valuation and Qualifying Accounts
Balance at Beginning of Period	35.5	31.6	36.0
Charged to Costs and Expenses	35.6	22.0	18.9
Charged to Other Accounts	120.0	0.0	0.0
Deductions	15.9	18.1	23.3
Balance at End of Period	175.2	35.5	31.6
SCE | All others
Movement in Valuation and Qualifying Accounts
Balance at Beginning of Period	13.9	19.5	17.3
Charged to Costs and Expenses	9.4	10.0	16.2
Charged to Other Accounts	0.0	0.0	0.0
Deductions	10.8	15.6	14.0
Balance at End of Period	$ 12.5	$ 13.9	$ 19.5