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Asset Retirement Obligations (Tables)
 12 Months Ended
Dec. 31, 2024
Asset Retirement Obligations Disclosure [Line Items]  
Summary of Asset Retirement Obligations By Type
The following table presents the Company's ARO liabilities by asset type as of December 31 (in millions):
20242023
Fossil-fueled generating facilities$477 $402 
Wind-powered generating facilities471 452 
Quad Cities Station428 407 
Solar-powered generating facilities37 36 
Offshore pipeline facilities15 15 
Other122 116 
Total asset retirement obligations$1,550 $1,428 
Quad Cities Station nuclear decommissioning trust funds$871 $767 
Reconciliation of Asset Retirement Obligation
The following table reconciles the beginning and ending balances of the Company's ARO liabilities for the years ended December 31 (in millions):
20242023
Beginning balance$1,428 $1,328 
Change in estimated costs63 54 
Additions39 56 
Retirements(38)(64)
Accretion58 54 
Ending balance$1,550 $1,428 
Reflected as:
Other current liabilities $63 $34 
Other long-term liabilities1,487 1,394 
Total ARO liability$1,550 $1,428 
PAC  
Asset Retirement Obligations Disclosure [Line Items]  
Reconciliation of Asset Retirement Obligation
The following table reconciles the beginning and ending balances of PacifiCorp's ARO liabilities for the years ended December 31 (in millions):
20242023
Beginning balance$356 $331 
Change in estimated costs73 (4)
Additions4 27 
Retirements(20)(9)
Accretion14 11 
Ending balance$427 $356 
Reflected as:
Other current liabilities$49 $9 
Other long-term liabilities378 347 
$427 $356 
MEC  
Asset Retirement Obligations Disclosure [Line Items]  
Summary of Asset Retirement Obligations By Type
The following table presents MidAmerican Energy's ARO liabilities by asset type as of December 31 (in millions):
20242023
Quad Cities Station$428 $407 
Wind-powered generating facilities318 305 
Fossil-fueled generating facilities79 62 
Solar-powered generating facilities and other4 4 
Total asset retirement obligations$829 $778 
Quad Cities Station nuclear decommissioning trust funds(1)
$871 $767 
(1)Refer to Note 6 for a discussion of the Quad Cities Station nuclear decommissioning trust funds.
Reconciliation of Asset Retirement Obligation
The following table reconciles the beginning and ending balances of MidAmerican Energy's ARO liabilities for the years ended December 31 (in millions):
20242023
Beginning balance$778 $707 
Change in estimated costs(2)56 
Additions20 3 
Retirements(1)(21)
Accretion34 33 
Ending balance$829 $778 
Reflected as:
Other current liabilities$6 $10 
Asset retirement obligations823 768 
$829 $778 
NPC  
Asset Retirement Obligations Disclosure [Line Items]  
Summary of Asset Retirement Obligations By Type
The following table presents Nevada Power's ARO liabilities by asset type as of December 31 (in millions):
20242023
Waste water remediation$31 $33 
Evaporative ponds and dry ash landfills12 12 
Solar-powered generating facilities6 6 
Other8 11 
Total asset retirement obligations$57 $62 
Reconciliation of Asset Retirement Obligation
The following table reconciles the beginning and ending balances of Nevada Power's ARO liabilities for the years ended December 31 (in millions):
20242023
Beginning balance$62 $59 
Change in estimated costs(3)6 
Additions3 3 
Retirements(8)(9)
Accretion3 3 
Ending balance$57 $62 
Reflected as:
Other current liabilities$5 $9 
Other long-term liabilities52 53 
$57 $62 
SPPC  
Asset Retirement Obligations Disclosure [Line Items]  
Summary of Asset Retirement Obligations By Type
The following table presents Sierra Pacific's ARO liabilities by asset type as of December 31 (in millions):
20242023
Asbestos$5 $5 
Evaporative ponds and dry ash landfills2 3 
Solar-powered generating facilities
1 1 
Other3 3 
Total asset retirement obligations$11 $12 
Reconciliation of Asset Retirement Obligation
The following table reconciles the beginning and ending balances of Sierra Pacific's ARO liabilities for the years ended December 31 (in millions):
20242023
Beginning balance$12 $11 
Change in estimated costs(2)— 
Additions— 1 
Accretion1 — 
Ending balance$11 $12 
Reflected as -
Other long-term liabilities$11 $12 
EEGH  
Asset Retirement Obligations Disclosure [Line Items]  
Reconciliation of Asset Retirement Obligation
The following table reconciles the beginning and ending balances of Eastern Energy Gas' ARO liabilities for the years ended December 31 (in millions):
20242023
Beginning balance$30 $48 
Retirements(3)(19)
Accretion1 1 
Ending balance$28 $30 
Reflected as:
Other current liabilities$3 $5 
Other long-term liabilities25 25 
Total ARO liability$28 $30 
EGTS  
Asset Retirement Obligations Disclosure [Line Items]  
Reconciliation of Asset Retirement Obligation
The following table reconciles the beginning and ending balances of EGTS' ARO liabilities for the years ended December 31 (in millions):

20242023
Beginning balance$30 $48 
Retirements(3)(19)
Accretion1 1 
Ending balance$28 $30 
Reflected as:
Current liabilities$3 $5 
Other long-term liabilities25 25 
Total ARO liability$28 $30