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Derivative Instruments (Details) - USD ($) $ in Millions	3 Months Ended
Derivative Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Indexed debt securities derivative \| Gains (Losses) in Other Income (Expense)
Derivatives, Fair Value [Line Items]
Gain (loss) on derivative instruments not designated as hedging instruments	$ (39)	$ 106
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative Assets Fair Value	1		$ 12
Derivative Liabilities Fair Value	617		578
Not Designated as Hedging Instrument \| CERC
Derivatives, Fair Value [Line Items]
Derivative Assets Fair Value	1		9
Derivative Liabilities Fair Value	0		0
Not Designated as Hedging Instrument \| Current Assets \| Energy Related Derivative
Derivatives, Fair Value [Line Items]
Derivative Assets Fair Value	1		9
Derivative Liabilities Fair Value	0		0
Not Designated as Hedging Instrument \| Current Assets \| Energy Related Derivative \| CERC
Derivatives, Fair Value [Line Items]
Derivative Assets Fair Value	1		7
Derivative Liabilities Fair Value	0		0
Not Designated as Hedging Instrument \| Current Assets \| Interest rate contract
Derivatives, Fair Value [Line Items]
Derivative Assets Fair Value	0		1
Derivative Liabilities Fair Value	0		0
Not Designated as Hedging Instrument \| Other Current Assets \| Energy Related Derivative
Derivatives, Fair Value [Line Items]
Derivative Assets Fair Value	0		2
Derivative Liabilities Fair Value	0		0
Not Designated as Hedging Instrument \| Other Current Assets \| Energy Related Derivative \| CERC
Derivatives, Fair Value [Line Items]
Derivative Assets Fair Value	0		2
Derivative Liabilities Fair Value	0		0
Not Designated as Hedging Instrument \| Current Liabilities \| Indexed debt securities derivative
Derivatives, Fair Value [Line Items]
Derivative Assets Fair Value	0		0
Derivative Liabilities Fair Value	617		578
Economic hedge \| Interest rate contract
Derivatives, Fair Value [Line Items]
Economic hedge	$ 84		$ 84