Asset Retirement Obligations (Notes)

12 Months Ended

Dec. 31, 2016

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, 2016 and 2015, respectively.

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

	2016		2015
Fossil fuel facilities	$	404	$	443
Quad Cities Station	343		289
Wind generating facilities	124		104
Offshore pipeline facilities	33		31
Solar generating facilities	12		12
Other	38		42
Total asset retirement obligations	$	954	$	921
Quad Cities Station nuclear decommissioning trust funds	$	460	$	429

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

	2016			2015
Beginning balance	$	921		$	753
Change in estimated costs	33			104
Additions	25			59
Retirements	(63		)	(32		)
Accretion	38			37
Ending balance	$	954		$	921
Reflected as:
Other current liabilities	$	98		$	92
Other long-term liabilities	856			829
Total ARO liability	$	954		$	921

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.

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 2016 change in estimated costs was primarily the result of a new decommissioning study conducted by the operator of the Quad Cities Station that changed the estimated amount and timing of cash flows. The 2015 change in estimated costs was primarily due to changes in the expected timing and amount 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, which 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 $917 million and $894 million as of December 31, 2016 and 2015, respectively.

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

	2016			2015
Beginning balance	$	224		$	135
Change in estimated costs	2			62
Additions	—			30
Retirements	(19		)	(10		)
Accretion	8			7
Ending balance	$	215		$	224
Reflected as:
Other current liabilities	$	21		$	35
Other long-term liabilities	194			189
	$	215		$	224

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 $665 million and $653 million as of December 31, 2016 and 2015, respectively.

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

	2016		2015
Quad Cities Station	$	343	$	289
Fossil-fueled generating facilities	132		160
Wind-powered generating facilities	91		82
Other	1		1
Total asset retirement obligations	$	567	$	532
Quad Cities Station nuclear decommissioning trust funds(1)	$	460	$	429

(1) Refer to Note 7 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):

	2016			2015
Beginning balance	$	532		$	460
Change in estimated costs	28			36
Additions	14			22
Retirements	(32		)	(9		)
Accretion	25			23
Ending balance	$	567		$	532
Reflected as:
Other current liabilities	$	57		$	44
Asset retirement obligations	510			488
	$	567		$	532

The change in estimated costs for 2016 was primarily the result of a new decommissioning study conducted by the operator of Quad Cities Station that changed the estimated amount and timing of cash flows. The change in estimated costs for 2015 was primarily due to changes in the expected timing and amount 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, which was effective in October 2015.

MidAmerican Funding, LLC and Subsidiaries [Domain]

Asset Retirement Obligations Disclosure [Line Items]

Asset Retirement Obligations [Text Block]

Asset Retirement Obligations

Refer to Note 12 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 $294 million and $273 million as of December 31, 2016 and 2015, respectively.

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

	2016		2015
Waste water remediation	$	38	$	42
Evaporative ponds and dry ash landfills	22		27
Asbestos	4		3
Solar	2		2
Other	17		11
Total asset retirement obligations	$	83	$	85

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

	2016			2015
Beginning balance	$	85		$	86
Change in estimated costs	4			3
Additions	—			3
Retirements	(10		)	(11		)
Accretion	4			4
Ending balance	$	83		$	85
Reflected as:
Other current liabilities	$	20		$	13
Other long-term liabilities	63			72
	$	83		$	85

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.

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 $205 million and $208 million as of December 31, 2016 and 2015, respectively.

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

	2016		2015
Asbestos	$	4	$	4
Evaporative ponds and dry ash landfills	3		3
Other	3		3
Total asset retirement obligations	$	10	$	10

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

	2016		2015
Beginning balance	$	10	$	11
Retirements	—		(1		)
Ending balance	$	10	$	10
Reflected as:
Other current liabilities	$	—	$	—
Other long-term liabilities	10		10
	$	10	$	10

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.