Regulatory Assets and Liabilities Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Regulatory Assets [Line Items]
Regulatory Assets	$ 837	$ 713
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	506
Regulatory Liabilities	1,493	1,446
Deferred Purchased Power Costs	78	5
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	1,199	1,173
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	179	177
Asset Retirement Obligation Costs [Member]
Regulatory Assets [Line Items]
Regulatory Liabilities	7	4
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	13
Regulatory Liabilities	75	96
Regulatory Assets Earning a Rate of Return at the Approved Rate	62
RemainingAmountsOfRegulatoryLiabilitesForWhichNoInterstAccruesDuringRecoveryPeriodIsProvided	13
Earning a return [Member]
Regulatory Assets [Line Items]
Regulatory Liabilities	1,480
Revenue Subject to Refund [Member]
Regulatory Assets [Line Items]
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	0
Regulatory Liabilities	40	0
Other Regulatory Assets Earning a Return [Member]
Regulatory Assets [Line Items]
Regulatory Assets	70
Earning a return [Member]
Regulatory Assets [Line Items]
Regulatory Assets	331
Deferred Derivative Gain (Loss) [Member]
Regulatory Assets [Line Items]
Regulatory Assets	0	206
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	185
Pension and Other Postretirement Plans Costs [Member]
Regulatory Assets [Line Items]
Regulatory Assets	0	104
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	84
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	161	139
Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets [Line Items]
Regulatory Assets	146	140
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	76
February2021IceStormAndDamageDeferral
Regulatory Assets [Line Items]
Regulatory Assets	58	67
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	0
2020LaborDayWildfireDeferral
Regulatory Assets [Line Items]
Regulatory Assets	24	28
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	43	29
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	0
January2024icestormanddamage
Regulatory Assets [Line Items]
Regulatory Assets	46	0
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	0
Reliabilitycontingencyevent
Regulatory Assets [Line Items]
Regulatory Assets	90	$ 0
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	$ 0