Equity (Details) - USD ($) shares in Millions, $ in Millions	1 Months Ended	3 Months Ended
	Feb. 29, 2020	Mar. 31, 2020	May 31, 2019
ATM
Class of Stock [Line Items]
Aggregate sales price (up to)			$ 1,500.0
Shares issued (in shares)		0.4
Proceeds received		$ 27.0
Offering expenses		0.3
Aggregate sales price remaining		1,300.0
401(k) defined contribution savings plan
Class of Stock [Line Items]
Proceeds received		$ 46.0
Issuance of new common stock (in shares)		0.7
Stock compensation awards
Class of Stock [Line Items]
Proceeds received		$ 13.0
Issuance of new common stock (in shares)		0.3
In lieu of dividend payment
Class of Stock [Line Items]
Proceeds received		$ 4.0
Issuance of new common stock (in shares)		0.1
Southern California Edison
Class of Stock [Line Items]
Capital contributions	$ 269.0