Regulatory Matters (Tables)

12 Months Ended

Dec. 31, 2017

Schedule Of Regulatory Assets and Liabilities [Line Items]

Regulatory assets represent costs that are expected to be recovered in future regulated rates. The Company's regulatory assets reflected on the Consolidated Balance Sheets consist of the following as of December 31 (in millions):



	Weighted
	Average
	Remaining Life	2017		2016

Employee benefit plans⁽¹⁾	16 years	$	675	$	816
Asset disposition costs	Various	387		281
Asset retirement obligations	13 years	334		301
Abandoned projects	3 years	156		159
Deferred operating costs	13 years	147		97
Deferred income taxes⁽²⁾	Various	143		1,754
Unrealized loss on regulated derivative contracts	4 years	122		154
Unamortized contract values	6 years	89		98
Deferred net power costs	2 years	58		38
Other	Various	839		759
Total regulatory assets		$	2,950	$	4,457

Reflected as:
Current assets		$	189	$	150
Noncurrent assets		2,761		4,307
Total regulatory assets		$	2,950	$	4,457


(1)	Represents amounts not yet recognized as a component of net periodic benefit cost that are expected to be included in regulated rates when recognized.


(2)	Amounts primarily represent income tax benefits related to certain property-related basis differences and other various differences that were previously passed on to customers and will be included in regulated rates when the temporary differences reverse.

Regulatory Liabilities [Table Text Block]

Regulatory liabilities represent income to be recognized or amounts to be returned to customers in future periods. The Company's regulatory liabilities reflected on the Consolidated Balance Sheets consist of the following as of December 31 (in millions):



	Weighted
	Average
	Remaining Life	2017		2016

Deferred income taxes⁽¹⁾	Various	$	4,143	$	25
Cost of removal⁽²⁾	27 years	2,349		2,242
Levelized depreciation	22 years	332		244
Asset retirement obligations	35 years	177		122
Impact fees	6 years	89		90
Employee benefit plans⁽³⁾	11 years	69		25
Deferred net power costs	2 years	8		64
Unrealized gain on regulated derivative contracts	1 year	3		6
Other	Various	341		302
Total regulatory liabilities		$	7,511	$	3,120

Reflected as:
Current liabilities		$	202	$	187
Noncurrent liabilities		7,309		2,933
Total regulatory liabilities		$	7,511	$	3,120

(1)

Amounts primarily represent income tax liabilities related to the federal tax rate change from 35% to 21% that are probable to be passed on to customers, offset by income tax benefits related to certain property-related basis differences and other various differences that were previously passed on to customers and will be included in regulated rates when the temporary differences reverse. See Note 11 for further discussion of 2017 Tax Reform impacts.


(2)	Amounts represent estimated costs, as accrued through depreciation rates and exclusive of ARO liabilities, of removing regulated property, plant and equipment in accordance with accepted regulatory practices. Amounts are deducted from rate base or otherwise accrue a carrying cost.


(3)	Represents amounts not yet recognized as a component of net periodic benefit cost that are to be returned to customers in future periods when recognized.

PacifiCorp [Member]

Schedule Of Regulatory Assets and Liabilities [Line Items]

Regulatory Assets [Table Text Block]

Regulatory assets represent costs that are expected to be recovered in future rates. PacifiCorp's regulatory assets reflected on the Consolidated Balance Sheets consist of the following as of December 31 (in millions):



	Weighted
	Average
	Remaining
	Life	2017		2016

Deferred income taxes⁽¹⁾	N/A	$	—	$	421
Employee benefit plans⁽²⁾	20 years	418		525
Utah mine disposition⁽³⁾	Various	156		166
Unamortized contract values	6 years	89		98
Deferred net power costs	1 year	21		33
Unrealized loss on derivative contracts	4 years	101		73
Asset retirement obligation	22 years	100		82
Other	Various	176		145
Total regulatory assets		$	1,061	$	1,543

Reflected as:
Current assets		$	31	$	53
Noncurrent assets		1,030		1,490
Total regulatory assets		$	1,061	$	1,543


(1)	Amount primarily represents income tax benefits and expense related to certain property-related basis differences and other various items that were previously passed on to customers and will be included in regulated rates when the temporary differences reverse.


(2)	Represents amounts not yet recognized as a component of net periodic benefit cost that are expected to be included in rates when recognized.


(3)	Amounts represent regulatory assets established as a result of the Utah mine disposition in 2015 for the net property, plant and equipment not considered probable of disallowance and for the portion of losses associated with the assets held for sale, UMWA 1974 Pension Plan withdrawal and closure costs incurred to date considered probable of recove

Regulatory Liabilities [Table Text Block]

Regulatory liabilities represent income to be recognized or amounts to be returned to customers in future periods. PacifiCorp's regulatory liabilities reflected on the Consolidated Balance Sheets consist of the following as of December 31 (in millions):



	Weighted
	Average
	Remaining
	Life	2017		2016

Cost of removal⁽¹⁾	26 years	$	955	$	917
Deferred income taxes⁽²⁾	Various	1,960		9
Other	Various	156		106
Total regulatory liabilities		$	3,071	$	1,032

Reflected as:
Current liabilities		$	75	$	54
Noncurrent liabilities		2,996		978
Total regulatory liabilities		$	3,071	$	1,032


(1)	Amounts represent estimated costs, as accrued through depreciation rates and exclusive of ARO liabilities, of removing property, plant and equipment in accordance with accepted regulatory practices. Amounts are deducted from rate base or otherwise accrue a carrying c

MidAmerican Energy Company [Member]

Schedule Of Regulatory Assets and Liabilities [Line Items]

Regulatory Assets [Table Text Block]

Regulatory assets represent costs that are expected to be recovered in future regulated rates. MidAmerican Energy's regulatory assets reflected on the Balance Sheets consist of the following as of December 31 (in millions):



	Average
	Remaining Life	2017		2016

Deferred income taxes, net⁽¹⁾	N/A	$	—	$	985
Asset retirement obligations⁽²⁾	10 years	133		105
Employee benefit plans⁽³⁾	13 years	38		40
Unrealized loss on regulated derivative contracts	1 year	6		2
Other	Various	27		29
Total		$	204	$	1,161


(1)	Amounts primarily represent income tax benefits related to state accelerated tax depreciation and certain property-related basis differences that were previously passed on to customers and will be included in regulated rates when the temporary differences reverse.


(2)	Amount predominantly relates to asset retirement obligations for fossil-fueled and wind-powered generating facilities. Refer to Note 12 for a discussion of asset retirement obligations.


(3)	Represents amounts not yet recognized as a component of net periodic benefit cost that are expected to be included in regulated rates when recognized.

Regulatory Liabilities [Table Text Block]

Regulatory liabilities represent income to be recognized or amounts to be returned to customers in future periods. MidAmerican Energy's regulatory liabilities reflected on the Balance Sheets consist of the following as of December 31 (in millions):



	Average
	Remaining Life	2017		2016

Cost of removal accrual⁽¹⁾	28 years	$	688	$	665
Deferred income taxes⁽²⁾	28 years	681		—
Asset retirement obligations⁽³⁾	35 years	173		117
Employee benefit plans⁽⁴⁾	11 years	41		12
Pre-funded AFUDC on transmission MVPs⁽⁵⁾	55 years	35		35
Iowa electric revenue sharing accrual⁽⁶⁾	1 year	26		30
Unrealized gain on regulated derivative contracts	1 year	3		6
Other	Various	14		18
Total		$	1,661	$	883


(1)	Amounts represent estimated costs, as accrued through depreciation rates and exclusive of ARO liabilities, of removing utility plant in accordance with accepted regulatory practices. Amounts are deducted from rate base or otherwise accrue a carrying cost.

(2)

Amounts primarily represent income tax liabilities related to the federal tax rate change from 35% to 21% that are probable to be passed on to customers, offset by income tax benefits related to state accelerated tax depreciation and certain property-related basis differences that were previously passed on to customers and will be included in regulated rates when the temporary differences reverse. See Note 10 for further discussion of 2017 Tax Reform impacts.


(3)	Amount predominantly represents the excess of nuclear decommission trust assets over the related asset retirement obligation. Refer to Note 12 for a discussion of asset retirement obligations.


(4)	Represents amounts not yet recognized as a component of net periodic benefit cost that are to be returned to customers in future periods when recognized.


(5)	Represents AFUDC accrued on transmission MVPs that is deducted from rate base as a result of the inclusion of related construction work-in-progress in rate base.


(6)	Represents current-year accruals under a regulatory arrangement in Iowa in which equity returns exceeding specified thresholds reduce utility plant upon final determination.

Nevada Power Company [Member]

Schedule Of Regulatory Assets and Liabilities [Line Items]

Regulatory Assets [Table Text Block]

Regulatory assets represent costs that are expected to be recovered in future rates. Nevada Power's regulatory assets reflected on the Consolidated Balance Sheets consist of the following as of December 31 (in millions):



	Weighted
	Average
	Remaining Life	2017		2016

Decommissioning costs	6 years	$	231	$	114
Deferred operating costs	12 years	169		127
Merger costs from 1999 merger	27 years	130		136
Employee benefit plans⁽¹⁾	8 years	89		105
Asset retirement obligations	7 years	72		74
Abandoned projects	3 years	58		75
Legacy meters	15 years	56		60
ON Line deferrals	36 years	47		44
Deferred energy costs	2 years	46		46
Deferred income taxes⁽²⁾	N/A	—		141
Other	Various	71		98
Total regulatory assets		$	969	$	1,020

Reflected as:
Current assets		$	28	$	20
Other assets		941		1,000
Total regulatory assets		$	969	$	1,020


(1)	Represents amounts not yet recognized as a component of net periodic benefit cost that are expected to be included in regulated rates when recognized.


(2)	Amounts primarily represent income tax benefits related to accelerated tax depreciation and certain property-related basis differences that were previously passed on to customers and will be included in regulated rates when the temporary differences reverse.

Regulatory Liabilities [Table Text Block]

Regulatory liabilities represent amounts to be returned to customers in future periods. Nevada Power's regulatory liabilities reflected on the Consolidated Balance Sheets consist of the following as of December 31 (in millions):



	Weighted
	Average
	Remaining Life	2017		2016

Deferred income taxes⁽¹⁾	33 years	$	670	$	9
Cost of removal⁽²⁾	31 years	307		294
Impact fees	6 years	89		90
Energy efficiency program	1 year	27		37
Other	Various	28		23
Total regulatory liabilities		$	1,121	$	453

Reflected as:
Current liabilities		$	91	$	37
Other long-term liabilities		1,030		416
Total regulatory liabilities		$	1,121	$	453

(1)

Amounts primarily represent income tax liabilities related to the federal tax rate change from 35% to 21% that are probable to be passed on to customers, offset by income tax benefits related to accelerated tax depreciation and certain property-related basis differences that were previously passed on to customers and will be included in regulated rates when the temporary differences reverse. See Note 10 for further discussion of 2017 Tax Reform impacts.


(2)	Amounts represent estimated costs, as accrued through depreciation rates and exclusive of ARO liabilities, of removing regulated property, plant and equipment in accordance with accepted regulatory practices. Amounts are deducted from rate base or otherwise accrue a carrying cost.

Sierra Pacific Power Company [Member]

Schedule Of Regulatory Assets and Liabilities [Line Items]

Regulatory Assets [Table Text Block]

Regulatory assets represent costs that are expected to be recovered in future rates. Sierra Pacific's regulatory assets reflected on the Consolidated Balance Sheets consist of the following as of December 31 (in millions):



	Weighted
	Average
	Remaining Life	2017		2016

Employee benefit plans⁽¹⁾	8 years	$	110	$	128
Merger costs from 1999 merger	29 years	77		80
Abandoned projects	7 years	34		39
Renewable energy programs	2 years	23		25
Losses on reacquired debt	16 years	21		22
Deferred income taxes⁽²⁾	N/A	—		85
Other	Various	67		56
Total regulatory assets		$	332	$	435

Reflected as:
Current assets		$	32	$	25
Other assets		300		410
Total regulatory assets		$	332	$	435


(1)	Represents amounts not yet recognized as a component of net periodic benefit cost that are expected to be included in regulated rates when recognized.


(2)	Amounts represent income tax benefits related to accelerated tax depreciation and certain property-related basis differences that were previously passed on to customers and will be included in regulated rates when the temporary differences reverse.

Regulatory Liabilities [Table Text Block]

Regulatory liabilities represent amounts to be returned to customers in future periods. Sierra Pacific's regulatory liabilities reflected on the Consolidated Balance Sheets consist of the following as of December 31 (in millions):



	Weighted
	Average
	Remaining Life	2017		2016

Deferred income taxes⁽¹⁾	29 years	$	264	$	6
Cost of removal⁽²⁾	41 years	211		205
Deferred energy costs	2 years	8		64
Other	Various	17		15
Total regulatory liabilities		$	500	$	290

Reflected as:
Current liabilities		$	19	$	69
Other long-term liabilities		481		221
Total regulatory liabilities		$	500	$	290

(1)

Amounts primarily represent income tax liabilities related to the federal tax rate change from 35% to 21% that are probable to be passed on to customers, offset by income tax benefits related to accelerated tax depreciation and certain property-related basis differences and other various differences that were previously passed on to customers and will be included in regulated rates when the temporary differences reverse. See Note 9 for further discussion of 2017 Tax Reform impacts.


(2)	Amounts represent estimated costs, as accrued through depreciation rates and exclusive of ARO liabilities, of removing regulated property, plant and equipment in accordance with accepted regulatory practices. Amounts are deducted from rate base or otherwise accrue a carrying cost.