Asset Retirement Obligations (Notes)

12 Months Ended

Dec. 31, 2015

Asset Retirement Obligations Disclosure [Line Items]

Asset Retirement Obligations [Text Block]

Asset Retirement Obligations

The Company estimates its ARO liabilities based upon detailed engineering calculations of the amount and timing of the future cash spending for a third party to perform the required work. Spending estimates are escalated for inflation and then discounted at a credit-adjusted, risk-free rate. Changes in estimates could occur for a number of reasons, including changes in laws and regulations, plan revisions, inflation and changes in the amount and timing of the expected work.

The Company does not recognize liabilities for AROs for which the fair value cannot be reasonably estimated. Due to the indeterminate removal date, the fair value of the associated liabilities on certain generation, transmission, distribution and other assets cannot currently be estimated, and no amounts are recognized on the Consolidated Financial Statements other than those included in the cost of removal regulatory liability established via approved depreciation rates in accordance with accepted regulatory practices. These accruals totaled $2.2 billion as of December 31, 2015 and 2014, respectively.

The following table presents the Company's ARO liabilities by asset type as of December 31 (in millions):

	2015		2014
Fossil fuel facilities	$	443	$	334
Quad Cities Station	289		265
Wind generating facilities	104		75
Offshore pipeline facilities	31		31
Solar generating facilities	12		9
Other	42		39
Total asset retirement obligations	$	921	$	753
Quad Cities Station nuclear decommissioning trust funds	$	429	$	424

The following table reconciles the beginning and ending balances of the Company's ARO liabilities for the years ended December 31 (in millions):

	2015			2014
Beginning balance	$	753		$	696
Acquisitions	—			12
Change in estimated costs	104			3
Additions	59			15
Retirements	(32		)	(8		)
Accretion	37			35
Ending balance	$	921		$	753
Reflected as:
Other current liabilities	$	92		$	66
Other long-term liabilities	829			687
Total ARO liability	$	921		$	753

The Nuclear Regulatory Commission regulates the decommissioning of nuclear power plants, which includes the planning and funding for the decommissioning. In accordance with these regulations, MidAmerican Energy submits a biennial report to the Nuclear Regulatory Commission providing reasonable assurance that funds will be available to pay for its share of the Quad Cities Station decommissioning. The decommissioning costs are included in base rates in MidAmerican Energy's Iowa tariffs.

Certain of the Company's decommissioning and reclamation obligations relate to jointly owned facilities and mine sites, and as such, each subsidiary is committed to pay a proportionate share of the decommissioning or reclamation costs. In the event of a default by any of the other joint participants, the respective subsidiary may be obligated to absorb, directly or by paying additional sums to the entity, a proportionate share of the defaulting party's liability. The Company's estimated share of the decommissioning and reclamation obligations are primarily recorded as ARO liabilities.

The 2015 change in estimated costs is primarily due to changes in the amount and timing of cash flows related to the implementation of the United States Environmental Protection Agency's final rule regulating the management and disposal of coal combustion byproducts resulting from the operation of coal-fueled generating facilities, including requirements for the operation and closure of surface impoundment and ash landfill facilities. The final rule was published in the Federal Register in April 2015 and was effective in October 2015. In addition to substantially impacting existing AROs, the final rule also resulted in the recognition of additional AROs.

PacifiCorp [Member]

Asset Retirement Obligations Disclosure [Line Items]

Asset Retirement Obligations [Text Block]

Asset Retirement Obligations

PacifiCorp estimates its ARO liabilities based upon detailed engineering calculations of the amount and timing of the future cash spending for a third party to perform the required work. Spending estimates are escalated for inflation and then discounted at a credit-adjusted, risk-free rate. Changes in estimates could occur for a number of reasons, including changes in laws and regulations, plan revisions, inflation and changes in the amount and timing of the expected work.

PacifiCorp does not recognize liabilities for AROs for which the fair value cannot be reasonably estimated. Due to the indeterminate removal date, the fair value of the associated liabilities on certain transmission, distribution and other assets cannot currently be estimated, and no amounts are recognized on the Consolidated Financial Statements other than those included in the cost of removal regulatory liability established via approved depreciation rates in accordance with accepted regulatory practices. Cost of removal regulatory liabilities totaled $894 million and $873 million as of December 31, 2015 and 2014, respectively.

The following table reconciles the beginning and ending balances of PacifiCorp's ARO liabilities for the years ended December 31 (in millions):

	2015			2014
Beginning balance	$	135		$	138
Change in estimated costs	62			(3		)
Additions	30			—
Retirements	(10		)	(6		)
Accretion	7			6
Ending balance	$	224		$	135
Reflected as:
Other current liabilities	$	35		$	21
Other long-term liabilities	189			114
	$	224		$	135

Certain of PacifiCorp's decommissioning and reclamation obligations relate to jointly owned facilities and mine sites. PacifiCorp is committed to pay a proportionate share of the decommissioning or reclamation costs. In the event of a default by any of the other joint participants, PacifiCorp may be obligated to absorb, directly or by paying additional sums to the entity, a proportionate share of the defaulting party's liability. PacifiCorp's estimated share of the decommissioning and reclamation obligations are primarily recorded as ARO liabilities.

In December 2014, the United States Environmental Protection Agency released its final rule regulating the management and disposal of coal combustion byproducts resulting from the operation of coal-fueled generating facilities, including requirements for the operation and closure of surface impoundment and ash landfill facilities. The final rule was published in the Federal Register in April 2015 and was effective in October 2015. The final rule substantially impacted existing AROs reflected in the December 31, 2015 change in estimated costs above and also resulted in the recognition of additional AROs.

MidAmerican Energy Company [Member]

Asset Retirement Obligations Disclosure [Line Items]

Asset Retirement Obligations [Text Block]

Asset Retirement Obligations

MidAmerican Energy estimates its ARO liabilities based upon detailed engineering calculations of the amount and timing of the future cash spending for a third party to perform the required work. Spending estimates are escalated for inflation and then discounted at a credit-adjusted, risk-free rate. Changes in estimates could occur for a number of reasons, including changes in laws and regulations, plan revisions, inflation and changes in the amount and timing of the expected work.

MidAmerican Energy does not recognize liabilities for AROs for which the fair value cannot be reasonably estimated. Due to the indeterminate removal date, the fair value of the associated liabilities on certain generation, transmission, distribution and other assets cannot currently be estimated, and no amounts are recognized on the Financial Statements other than those included in the cost of removal regulatory liability established via approved depreciation rates in accordance with accepted regulatory practices. These accruals totaled $653 million and $642 million as of December 31, 2015 and 2014, respectively.

The following table presents MidAmerican Energy's ARO liabilities by asset type as of December 31, (in millions):

	2015		2014
Quad Cities Station	$	289	$	265
Fossil-fueled generating facilities	160		132
Wind-powered generating facilities	82		60
Other	1		3
Total asset retirement obligations	$	532	$	460
Quad Cities Station nuclear decommissioning trust funds(1)	$	429	$	424

(1) Refer to Note 6 for a discussion of the Quad Cities Station nuclear decommissioning trust funds.

The following table reconciles the beginning and ending balances of MidAmerican Energy's ARO liabilities for the years ended December 31, (in millions):

	2015			2014
Beginning balance	$	460		$	430
Change in estimated costs	36			(2		)
Additions	22			11
Retirements	(9		)	—
Accretion	23			21
Ending balance	$	532		$	460
Reflected as:
Other current liabilities	$	44		$	28
Asset retirement obligations	488			432
	$	532		$	460

In December 2014, the United States Environmental Protection Agency released its final rule regulating the management and disposal of coal combustion byproducts resulting from the operation of coal-fueled generating facilities, including requirements for the operation and closure of surface impoundment and ash landfill facilities. The final rule, which was effective in October 2015, resulted in increases to MidAmerican Energy's ARO liabilities due to changes in the expected timing and amount of cash flow for ash pond closures at some of MidAmerican Energy's thermal generating facilities.

MidAmerican Funding, LLC and Subsidiaries [Domain]

Asset Retirement Obligations Disclosure [Line Items]

Asset Retirement Obligations [Text Block]

Asset Retirement Obligations

Refer to Note 11 of MidAmerican Energy's Notes to Financial Statements.

Nevada Power Company [Member]

Asset Retirement Obligations Disclosure [Line Items]

Asset Retirement Obligations [Text Block]

Asset Retirement Obligations

Nevada Power estimates its ARO liabilities based upon detailed engineering calculations of the amount and timing of the future cash spending for a third party to perform the required work. Spending estimates are escalated for inflation and then discounted at a credit-adjusted, risk-free rate. Changes in estimates could occur for a number of reasons, including changes in laws and regulations, plan revisions, inflation and changes in the amount and timing of the expected work.

Nevada Power does not recognize liabilities for AROs for which the fair value cannot be reasonably estimated. Due to the indeterminate removal date, the fair value of the associated liabilities on certain generation, transmission, distribution and other assets cannot currently be estimated, and no amounts are recognized on the Consolidated Financial Statements other than those included in the cost of removal regulatory liability established via approved depreciation rates in accordance with accepted regulatory practices. These accruals totaled $273 million and $295 million as of December 31, 2015 and 2014, respectively.

The following table presents Nevada Power's ARO liabilities by asset type as of December 31 (in millions):

	2015		2014
Waste water remediation	$	42	$	53
Evaporative ponds and dry ash landfills	27		25
Asbestos	3		3
Other	13		5
Total asset retirement obligations	$	85	$	86

The following table reconciles the beginning and ending balances of Nevada Power's ARO liabilities for the years ended December 31 (in millions):

	2015			2014
Beginning balance	$	86		$	100
Change in estimated costs	3			(18		)
Additions	3			—
Retirements	(11		)	—
Accretion	4			4
Ending balance	$	85		$	86
Reflected as:
Other current liabilities	$	13		$	14
Other long-term liabilities	72			72
	$	85		$	86

In 2008, Nevada Power signed an administrative order of consent as owner and operator of Reid Gardner Generating Station Unit Nos. 1, 2 and 3 and as co-owner and operating agent of Unit No. 4. Based on the administrative order of consent, Nevada Power recorded estimated AROs and capital remediation costs. However, actual costs of work under the administrative order of consent may vary significantly once the scope of work is defined and additional site characterization has been completed. In connection with the termination of the co-ownership arrangement, effective October 22, 2013, between Nevada Power and California Department of Water Resources ("CDWR") for the Reid Gardner Generating Station Unit No. 4, Nevada Power and CDWR entered into a cost-sharing agreement that sets forth how the parties will jointly share in costs associated with all investigation, characterization and, if necessary, remedial activities as required under the administrative order of consent. The 2014 change in estimated costs was related to refinement of expected remediation costs at the Reid Gardner Generating Station and impacts of the new coal combustion rule.

Certain of Nevada Power's decommissioning and reclamation obligations relate to jointly-owned facilities, and as such, Nevada Power is committed to pay a proportionate share of the decommissioning or reclamation costs. In the event of a default by any of the other joint participants, the respective subsidiary may be obligated to absorb, directly or by paying additional sums to the entity, a proportionate share of the defaulting party's liability. Management has identified legal obligations to retire generation plant assets specified in land leases for Nevada Power's jointly-owned Navajo Generating Station and the Higgins Generating Station. Provisions of the lease require the lessees to remove the facilities upon request of the lessors at the expiration of the leases. Nevada Power's estimated share of the decommissioning and reclamation obligations are primarily recorded as ARO liabilities in other long-term liabilities on the Consolidated Balance Sheets.

The 2015 change in estimated costs is primarily due to changes in the amount and timing of cash flows related to the implementation of the United States Environmental Protection Agency's ("EPA") final rule regulating the management and disposal of coal combustion byproducts resulting from the operation of coal-fueled generating facilities, including requirements for the operation and closure of surface impoundment and ash landfill facilities. The final rule was published in the Federal Register in April 2015 and was effective in October 2015. In addition to impacting existing AROs, the final rule also resulted in the recognition of additional AROs.

Sierra Pacific Power Company [Member]

Asset Retirement Obligations Disclosure [Line Items]

Asset Retirement Obligations [Text Block]

Asset Retirement Obligations

Sierra Pacific estimates its ARO liabilities based upon detailed engineering calculations of the amount and timing of the future cash spending for a third party to perform the required work. Spending estimates are escalated for inflation and then discounted at a credit-adjusted, risk-free rate. Changes in estimates could occur for a number of reasons, including changes in laws and regulations, plan revisions, inflation and changes in the amount and timing of the expected work.

Sierra Pacific does not recognize liabilities for AROs for which the fair value cannot be reasonably estimated. Due to the indeterminate removal date, the fair value of the associated liabilities on certain generation, transmission, distribution and other assets cannot currently be estimated, and no amounts are recognized on the Consolidated Financial Statements other than those included in the cost of removal regulatory liability established via approved depreciation rates in accordance with accepted regulatory practices. These accruals totaled $208 million and $233 million as of December 31, 2015 and 2014, respectively.

The following table presents Sierra Pacific's ARO liabilities by asset type as of December 31 (in millions):

	2015		2014
Asbestos	$	4	$	5
Evaporative ponds and dry ash landfills	3		2
Other	3		4
Total asset retirement obligations	$	10	$	11

The following table reconciles the beginning and ending balances of Sierra Pacific's ARO liabilities for the years ended December 31 (in millions):

	2015			2014
Beginning balance	$	11		$	16
Change in estimated costs	—			(6		)
Retirements	(1		)	—
Accretion	—			1
Ending balance	$	10		$	11
Reflected as:
Other current liabilities	$	—		$	3
Other long-term liabilities	10			8
	$	10		$	11

Certain of Sierra Pacific's decommissioning and reclamation obligations relate to jointly-owned facilities, and as such, Sierra Pacific is committed to pay a proportionate share of the decommissioning or reclamation costs. In the event of a default by any of the other joint participants, the respective subsidiary may be obligated to absorb, directly or by paying additional sums to the entity, a proportionate share of the defaulting party's liability. Sierra Pacific's estimated share of the decommissioning and reclamation obligations are primarily recorded as ARO liabilities in other long-term liabilities on the Consolidated Balance Sheets.

In December 2014, the United States Environmental Protection Agency ("EPA") released its final rule regulating the management and disposal of coal combustion byproducts resulting from the operation of coal-fueled generating facilities, including requirements for the operation and closure of surface impoundment and ash landfill facilities. The final rule was published in the Federal Register in April 2015 and was effective in October 2015. The effects of the new rule did not have a material impact on Sierra Pacific's ARO balance. The impact of this new rule is reflected in the December 31, 2015 change in estimated costs above.