Risk Management and Hedging Activities - PAC - Balance Sheet Location (Details) - PAC - Commodity derivatives - USD ($) $ in Millions	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Total	$ 166		$ 53
Cash collateral payable	(23)		5
Total derivatives - net basis	143		58
Derivative Contracts - Current Assets
Derivatives, Fair Value [Line Items]
Total	124		76
Cash collateral payable	(16)		0
Total derivatives - net basis	108		76
Other Assets
Derivatives, Fair Value [Line Items]
Total	48		20
Cash collateral payable	(7)		0
Total derivatives - net basis	41		20
Other Current Liabilities
Derivatives, Fair Value [Line Items]
Total	(6)		(36)
Cash collateral payable	0		5
Total derivatives - net basis	(6)		(31)
Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Total	0		(7)
Cash collateral payable	0		0
Total derivatives - net basis	0		(7)
Not Designated as Hedging
Derivatives, Fair Value [Line Items]
Derivative asset, gross	203		104
Derivative liability	(37)		(51)
Total	166		53
Net regulatory asset (liability) on derivative contracts	(166)	$ (223)	(53)	$ (149)	$ (102)	$ 17
Not Designated as Hedging | Derivative Contracts - Current Assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross	144		81
Derivative liability	(20)		(5)
Total	124		76
Not Designated as Hedging | Other Assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross	52		21
Derivative liability	(4)		(1)
Total	48		20
Not Designated as Hedging | Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative asset, gross	7		2
Derivative liability	(13)		(38)
Total	(6)		(36)
Not Designated as Hedging | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative asset, gross	0		0
Derivative liability	0		(7)
Total	$ 0		$ (7)