Regulatory Assets and Liabilities, Regulatory Assets (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021
Regulatory Assets [Line Items]
Regulatory Asset, Current		$ 1,059	$ 1,106
Regulatory Asset, Noncurrent		(2,871)	(2,738)
Regulatory assets not currently earning a return		1,020	1,718
Pension and retiree medical obligations
Regulatory Assets [Line Items]
Regulatory Asset, Current		22	77	[1]
Regulatory Asset, Noncurrent		(1,069)	(944)	[1]
Net AROs
Regulatory Assets [Line Items]
Regulatory Asset, Current	[2]	0	0	[1]
Regulatory Asset, Noncurrent	[2]	(339)	(112)	[1]
Deferred purchased natural gas and electric energy costs
Regulatory Assets [Line Items]
Regulatory Asset, Current		581	504	[1]
Regulatory Asset, Noncurrent		$ (299)	(543)	[1]
Deferred purchased natural gas and electric energy costs | Minimum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		1 year
Deferred purchased natural gas and electric energy costs | Maximum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		5 years
Recoverable deferred taxes on AFUDC recorded in plant
Regulatory Assets [Line Items]
Regulatory Asset, Current		$ 0	0	[1]
Regulatory Asset, Noncurrent		(292)	(289)	[1]
Excess deferred taxes - TCJA
Regulatory Assets [Line Items]
Regulatory Asset, Current		13	14	[1]
Regulatory Asset, Noncurrent		(205)	(219)	[1]
Depreciation differences
Regulatory Assets [Line Items]
Regulatory Asset, Current		17	16	[1]
Regulatory Asset, Noncurrent		$ (193)	(173)	[1]
Depreciation differences | Minimum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		1 year
Depreciation differences | Maximum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		12 years
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory Asset, Current		$ 20	14	[1]
Regulatory Asset, Noncurrent		(92)	(92)	[1]
Benson Biomass PPA termination and asset purchase
Regulatory Assets [Line Items]
Regulatory Asset, Current		10	10	[1]
Regulatory Asset, Noncurrent		$ (45)	(55)	[1]
Regulatory Asset, Remaining Amortization Period		6 years
PI extended power update
Regulatory Assets [Line Items]
Regulatory Asset, Current		$ 4	4	[1]
Regulatory Asset, Noncurrent		$ (42)	(46)	[1]
Regulatory Asset, Remaining Amortization Period		12 years
Conservation programs
Regulatory Assets [Line Items]
Regulatory Asset, Current	[3]	$ 16	21	[1]
Regulatory Asset, Noncurrent	[3]	$ (36)	(35)	[1]
Conservation programs | Minimum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		1 year
Conservation programs | Maximum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		2 years
Purchased power contract costs
Regulatory Assets [Line Items]
Regulatory Asset, Current		$ 10	9	[1]
Regulatory Asset, Noncurrent		(36)	(45)	[1]
State commission adjustments
Regulatory Assets [Line Items]
Regulatory Asset, Current		1	1	[1]
Regulatory Asset, Noncurrent		(33)	(32)	[1]
Losses on reacquired debt
Regulatory Assets [Line Items]
Regulatory Asset, Current		3	3	[1]
Regulatory Asset, Noncurrent		(32)	(35)	[1]
Contract valuation adjustments
Regulatory Assets [Line Items]
Regulatory Asset, Current	[4]	28	22	[1]
Regulatory Asset, Noncurrent	[4]	(28)	(34)	[1]
Grid modernization costs
Regulatory Assets [Line Items]
Regulatory Asset, Current		14	0	[1]
Regulatory Asset, Noncurrent		(24)	(36)	[1]
Gas pipeline inspection and remediation costs
Regulatory Assets [Line Items]
Regulatory Asset, Current		42	33	[1]
Regulatory Asset, Noncurrent		$ (13)	(12)	[1]
Gas pipeline inspection and remediation costs | Minimum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		1 year
Gas pipeline inspection and remediation costs | Maximum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		2 years
Nuclear refueling outage costs
Regulatory Assets [Line Items]
Regulatory Asset, Current		$ 30	37	[1]
Regulatory Asset, Noncurrent		$ (12)	(16)	[1]
Nuclear refueling outage costs | Minimum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		1 year
Nuclear refueling outage costs | Maximum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		2 years
Renewable resources and environmental initiatives
Regulatory Assets [Line Items]
Regulatory Asset, Current		$ 50	170	[1]
Regulatory Asset, Noncurrent		$ (6)	(48)	[1]
Renewable resources and environmental initiatives | Minimum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		1 year
Renewable resources and environmental initiatives | Maximum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		2 years
Texas revenue surcharges
Regulatory Assets [Line Items]
Regulatory Asset, Current		$ 69	20	[1]
Regulatory Asset, Noncurrent		$ 0	(64)	[1]
Texas revenue surcharges | Minimum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		1 year
Sales true-up and revenue decoupling
Regulatory Assets [Line Items]
Regulatory Asset, Current		$ 54	33	[1]
Regulatory Asset, Noncurrent		$ 0	(56)	[1]
Sales true-up and revenue decoupling | Minimum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		1 year
Sales true-up and revenue decoupling | Maximum
Regulatory Assets [Line Items]
Regulatory Asset, Remaining Amortization Period		2 years
Other
Regulatory Assets [Line Items]
Regulatory Asset, Current		$ 75	118	[1]
Regulatory Asset, Noncurrent		$ (75)	$ (76)	[1]

[1] Prior period amounts have been restated to conform with current year presentation.

[2] Includes amounts recorded for future recovery of AROs, less amounts recovered through nuclear decommissioning accruals and gains from decommissioning investments.

[3] Includes costs for conservation programs, as well as incentives allowed in certain jurisdictions.

[4] Includes the fair value of certain long-term PPAs used to meet energy capacity requirements and valuation adjustments on natural gas commodity purchases