Regulatory Assets and Liabilities Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Regulatory Assets [Line Items]
Regulatory Assets	$ 527	$ 557
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	274
Regulatory Liabilities	1,623	1,466
Deferred Purchased Power Costs	23	62
Removal Costs [Member]
Regulatory Assets [Line Items]
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	0
Regulatory Liabilities	1,136	1,047
Deferred Income Tax Charge [Member]
Regulatory Assets [Line Items]
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	0
Regulatory Liabilities	194	208
Asset Retirement Obligation Costs [Member]
Regulatory Assets [Line Items]
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	0
Regulatory Liabilities	7	43
Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets [Line Items]
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	24
Regulatory Liabilities	91	113
Regulatory Assets Earning a Rate of Return at the Approved Rate	67
RemainingAmountsOfRegulatoryLiabilitesForWhichNoInterstAccruesDuringRecoveryPeriodIsProvided	219
Deferred Derivative Gain (Loss) [Member]
Regulatory Assets [Line Items]
Regulatory Assets		55
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	195
Regulatory Liabilities	0
Earning a return [Member]
Regulatory Assets [Line Items]
Regulatory Liabilities	1,404
Other Regulatory Assets Earning a Return [Member]
Regulatory Assets [Line Items]
Regulatory Assets	70
Earning a return [Member]
Regulatory Assets [Line Items]
Regulatory Assets	253
Deferred Derivative Gain (Loss) [Member]
Regulatory Assets [Line Items]
Regulatory Assets	0	55
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	1
Pension and Other Postretirement Plans Costs [Member]
Regulatory Assets [Line Items]
Regulatory Assets	0	131
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	95
Loss on Reacquired Debt [Member]
Regulatory Assets [Line Items]
Regulatory Assets	0	23
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	21
Environmental Restoration Costs [Member]
Regulatory Assets [Line Items]
Regulatory Assets	0
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	133	90
Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets [Line Items]
Regulatory Assets	94	81
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	24
February2021IceStormAndDamageDeferral
Regulatory Assets [Line Items]
Regulatory Assets	74	67
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	0
PowerCostAdjustmentMechanismDeferral
Regulatory Assets [Line Items]
Regulatory Assets	28	29
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	0
2020LaborDayWildfireDeferral
Regulatory Assets [Line Items]
Regulatory Assets	31	45
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	0
COVID-19Deferral
Regulatory Assets [Line Items]
Regulatory Assets	22	36
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	0
Wildfire mitigation
Regulatory Assets [Line Items]
Regulatory Assets	28	$ 0
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	$ 0