Risk Management and Hedging Activities - PAC - Balance Sheet Location (Details) - PAC - Commodity derivatives - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Total	$ 109	$ 270
Cash collateral payable	(12)	(78)
Total derivatives - net basis	97	192
Cash collateral payable, not offset		12
Derivative Contracts - Current Assets
Derivatives, Fair Value [Line Items]
Total	126	257
Cash collateral payable	(12)	(73)
Total derivatives - net basis	114	184
Other Assets
Derivatives, Fair Value [Line Items]
Total	8	20
Cash collateral payable	0	(5)
Total derivatives - net basis	8	15
Other Current Liabilities
Derivatives, Fair Value [Line Items]
Total	(24)	(5)
Cash collateral payable	0	0
Total derivatives - net basis	(24)	(5)
Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Total	(1)	(2)
Cash collateral payable	0	0
Total derivatives - net basis	(1)	(2)
Not Designated as Hedging
Derivatives, Fair Value [Line Items]
Derivative asset, gross	166	318
Derivative liability	(57)	(48)
Total	109	270
Net regulatory asset (liability) on derivative contracts	(109)	(270)	$ (195)	$ (53)
Not Designated as Hedging | Derivative Contracts - Current Assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross	133	279
Derivative liability	(7)	(22)
Total	126	257
Not Designated as Hedging | Other Assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross	15	27
Derivative liability	(7)	(7)
Total	8	20
Not Designated as Hedging | Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative asset, gross	15	9
Derivative liability	(39)	(14)
Total	(24)	(5)
Not Designated as Hedging | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative asset, gross	3	3
Derivative liability	(4)	(5)
Total	$ (1)	$ (2)