Regulatory Matters - PAC - Regulatory Assets (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Regulatory Assets [Line Items]
Total regulatory assets	$ 5,565	$ 5,062
Regulatory assets, current	1,398	1,319
Regulatory assets, noncurrent	4,167	3,743
Regulatory assets not earning a return on investment	$ 3,200	2,300
Employee benefit plans
Regulatory Assets [Line Items]
Regulatory asset, amortization period	14 years
Total regulatory assets	$ 414	490
Deferred net power costs
Regulatory Assets [Line Items]
Regulatory asset, amortization period	2 years
Total regulatory assets	$ 1,769	1,478
Unrealized loss on regulated derivative contracts
Regulatory Assets [Line Items]
Regulatory asset, amortization period	1 year
Total regulatory assets	$ 173	112
Environmental costs
Regulatory Assets [Line Items]
Regulatory asset, amortization period	30 years
Total regulatory assets	$ 139	111
Asset retirement obligations
Regulatory Assets [Line Items]
Regulatory asset, amortization period	17 years
Total regulatory assets	$ 930	835
Demand side management
Regulatory Assets [Line Items]
Regulatory asset, amortization period	10 years
Total regulatory assets	$ 245	224
Wildfire mitigation and vegetation management costs
Regulatory Assets [Line Items]
Total regulatory assets	114	111
PAC
Regulatory Assets [Line Items]
Total regulatory assets	2,573	1,880
Regulatory assets, current	631	275
Regulatory assets, noncurrent	1,942	1,605
Regulatory assets not earning a return on investment	$ 1,852	1,200
PAC | Employee benefit plans
Regulatory Assets [Line Items]
Regulatory asset, amortization period	16 years
Total regulatory assets	$ 279	290
PAC | Utah mine disposition
Regulatory Assets [Line Items]
Total regulatory assets	$ 79	115
PAC | Deferred net power costs
Regulatory Assets [Line Items]
Regulatory asset, amortization period	2 years
Total regulatory assets	$ 1,117	546
PAC | Unrealized loss on regulated derivative contracts
Regulatory Assets [Line Items]
Regulatory asset, amortization period	1 year
Total regulatory assets	$ 76	0
PAC | Environmental costs
Regulatory Assets [Line Items]
Regulatory asset, amortization period	30 years
Total regulatory assets	$ 139	111
PAC | Asset retirement obligations
Regulatory Assets [Line Items]
Regulatory asset, amortization period	28 years
Total regulatory assets	$ 300	275
PAC | Demand side management
Regulatory Assets [Line Items]
Regulatory asset, amortization period	10 years
Total regulatory assets	$ 245	224
PAC | Wildfire mitigation and vegetation management costs
Regulatory Assets [Line Items]
Total regulatory assets	114	111
PAC | Other
Regulatory Assets [Line Items]
Total regulatory assets	$ 224	$ 208