Risk Management and Hedging Activities - PAC - Balance Sheet Location (Details) - PAC - Commodity derivatives - USD ($) $ in Millions	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Total	$ 50		$ 270
Cash collateral (payable) receivable	(3)		(78)
Total derivatives - net basis	47		192
Cash collateral payable, not offset			12
Derivative Contracts - Current Assets
Derivatives, Fair Value [Line Items]
Total	55		257
Cash collateral (payable) receivable	(8)		(73)
Total derivatives - net basis	47		184
Other Assets
Derivatives, Fair Value [Line Items]
Total	7		20
Cash collateral (payable) receivable	0		(5)
Total derivatives - net basis	7		15
Other Current Liabilities
Derivatives, Fair Value [Line Items]
Total	(12)		(5)
Cash collateral (payable) receivable	5		0
Total derivatives - net basis	(7)		(5)
Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Total	0		(2)
Cash collateral (payable) receivable	0		0
Total derivatives - net basis	0		(2)
Not Designated as Hedging
Derivatives, Fair Value [Line Items]
Derivative asset, gross	82		318
Derivative liability	(32)		(48)
Total	50		270
Net regulatory asset (liability) on derivative contracts	(50)	$ (9)	(270)	$ (166)	$ (223)	$ (53)
Not Designated as Hedging | Derivative Contracts - Current Assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross	66		279
Derivative liability	(11)		(22)
Total	55		257
Not Designated as Hedging | Other Assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross	11		27
Derivative liability	(4)		(7)
Total	7		20
Not Designated as Hedging | Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative asset, gross	5		9
Derivative liability	(17)		(14)
Total	(12)		(5)
Not Designated as Hedging | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative asset, gross	0		3
Derivative liability	0		(5)
Total	$ 0		$ (2)