Variable Interest Entities - Additional Information (Details) - Clean Energy Businesses - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Con Edison Development | CED Nevada Virginia
Variable Interest Entity [Line Items]
Income before tax	$ 39
Income after tax	30
Variable Interest Entity, Primary Beneficiary | Tax Equity Projects
Variable Interest Entity [Line Items]
Income (loss) before tax	10
Net income (loss)	7
Variable Interest Entity, Primary Beneficiary | Tax Equity Investors | Tax Equity Projects
Variable Interest Entity [Line Items]
Income (loss) before tax	5	$ 2
Net income (loss)		1
Measure of activity, loss, after tax	4
Variable Interest Entity, Primary Beneficiary | Tax Equity Investors | CED Nevada Virginia
Variable Interest Entity [Line Items]
Income (loss) before tax	(42)
Net income (loss)	$ (32)
Variable Interest Entity, Primary Beneficiary | Con Edison Development | Tax Equity Projects
Variable Interest Entity [Line Items]
Income (loss) before tax		(3)
Net income (loss)		$ (2)
Percentage of variable interests (less than)	100.00%