Fair Value Measurements (MEC) (Tables) (MidAmerican Energy Company and Subsidiaries [Member])

12 Months Ended

Dec. 31, 2012

MidAmerican Energy Company and Subsidiaries [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

The following table presents the fair value of plan assets, by major category, for MidAmerican Energy's defined benefit pension plan (in millions):

	Input Levels for Fair Value Measurements(1)
	Level 1		Level 2		Level 3		Total
As of December 31, 2012
Cash equivalents	$	—	$	7	$	—	$	7
Debt securities:
United States government obligations	19		—		—		19
Corporate obligations	—		31		—		31
Municipal obligations	—		5		—		5
Agency, asset and mortgage-backed obligations	—		29		—		29
Equity securities:
United States companies	137		—		—		137
Investment funds(2)	101		288		—		389
Real estate funds	—		—		26		26
Total	$	257	$	360	$	26	$	643
As of December 31, 2011
Cash equivalents	$	—	$	9	$	—	$	9
Debt securities:
United States government obligations	6		—		—		6
Corporate obligations	—		29		—		29
Municipal obligations	—		5		—		5
Agency, asset and mortgage-backed obligations	—		35		—		35
Equity securities:
United States companies	115		—		—		115
Investment funds(2)	76		256		—		332
Real estate funds	—		—		24		24
Total	$	197	$	334	$	24	$	555

(1) Refer to Note 14 for additional discussion regarding the three levels of the fair value hierarchy.

(2) Investment funds are comprised of mutual funds and collective trust funds. These funds consist of equity and debt securities of approximately 74% and 26%, respectively, for 2012 and 77% and 23%, respectively, for 2011. Additionally, these funds are invested in United States and international securities of approximately 77% and 23%, respectively, for 2012 and 79% and 21%, respectively, for 2011.

The following table presents the fair value of plan assets, by major category, for MidAmerican Energy's defined benefit other postretirement plans (in millions):

	Input Levels for Fair Value Measurements(1)
	Level 1		Level 2		Level 3		Total
As of December 31, 2012
Cash equivalents	$	2	$	—	$	—	$	2
Debt securities:
United States government obligations	4		—		—		4
Corporate obligations	—		9		—		9
Municipal obligations	—		32		—		32
Agency, asset and mortgage-backed obligations	—		14		—		14
Equity securities:
United States companies	102		—		—		102
Investment funds(2)	63		—		—		63
Total	$	171	$	55	$	—	$	226
As of December 31, 2011
Cash equivalents	$	6	$	—	$	—	$	6
Debt securities:
United States government obligations	6		—		—		6
Corporate obligations	—		7		—		7
Municipal obligations	—		30		—		30
Agency, asset and mortgage-backed obligations	—		12		—		12
Equity securities:
United States companies	88		—		—		88
Investment funds(2)	64		—		—		64
Total	$	164	$	49	$	—	$	213

(1) Refer to Note 14 for additional discussion regarding the three levels of the fair value hierarchy.

(2) Investment funds are comprised of mutual funds and collective trust funds. These funds consist of equity and debt securities of approximately 86% and 14%, respectively, for 2012 and 83% and 17%, respectively, for 2011. Additionally, these funds are invested in United States and international securities of approximately 51% and 49%, respectively, for 2012 and 59% and 41%, respectively, for 2011.

The following table presents MidAmerican Energy's assets and liabilities recognized on the Consolidated Balance Sheets and measured at fair value on a recurring basis (in millions):

	Input Levels for Fair Value Measurements
	Level 1			Level 2			Level 3			Other(1)			Total
As of As of December 31, 2012:
Assets:
Commodity derivatives	$	1		$	22		$	7		$	(23	)	$	7
Money market mutual funds(2)	163			—			—			—			163
Debt securities:
United States government obligations	104			—			—			—			104
International government obligations	—			1			—			—			1
Corporate obligations	—			32			—			—			32
Municipal obligations	—			4			—			—			4
Agency, asset and mortgage-backed obligations	—			6			—			—			6
Auction rate securities	—			—			21			—			21
Equity securities:
United States companies	187			—			—			—			187
International companies	2			—			—			—			2
Investment funds	1			—			—			—			1
	$	458		$	65		$	28		$	(23	)	$	528
Liabilities - commodity derivatives	$	(10	)	$	(90	)	$	(7	)	$	30		$	(77	)
As of As of December 31, 2011:
Assets:
Commodity derivatives	$	1		$	47		$	26		$	(45	)	$	29
Debt securities:
United States government obligations	89			—			—			—			89
International government obligations	—			1			—			—			1
Corporate obligations	—			30			—			—			30
Municipal obligations	—			12			—			—			12
Agency, asset and mortgage-backed obligations	—			7			—			—			7
Auction rate securities	—			—			16			—			16
Equity securities:
United States companies	166			—			—			—			166
International companies	1			—			—			—			1
	$	257		$	97		$	42		$	(45	)	$	351
Liabilities - commodity derivatives	$	(37	)	$	(148	)	$	(4	)	$	78		$	(111	)

(1) Represents netting under master netting arrangements and a net cash collateral receivable of $7 million and $33 million as of December 31, 2012 and 2011, respectively.

(2) Amounts are included in cash and cash equivalents and investments and nonregulated property, net on the Consolidated Balance Sheets. The fair value of these money market mutual funds approximates cost.

Fair Value Assets and Liabilities Net Measured On Recurring Basis Unobservable Input Reconciliation [Table Text Block]

The following table reconciles the beginning and ending balances of MidAmerican Energy's assets measured at fair value on a recurring basis using significant Level 3 inputs for the years ended December 31 (in millions):

	Commodity Derivatives									Auction Rate Securities
	2012			2011			2010			2012		2011			2010
Beginning balance	$	22		$	14		$	21		$	16	$	20		$	16
Changes included in earnings(1)	5			23			14			—		—			—
Changes in fair value recognized in OCI	—			(3		)	—			5		1			4
Changes in fair value recognized in net regulatory assets	(3		)	12			5			—		—			—
Sales	—			—			—			—		(5		)	—
Settlements	(24		)	(25		)	(29		)	—		—			—
Transfers to Level 2	—			—			3			—		—			—
Transfers from Level 2	—			1			—			—		—			—
Ending balance	$	—		$	22		$	14		$	21	$	16		$	20

(1) Changes included in earnings are reported as nonregulated operating revenue on the Consolidated Statements of Operations. Net unrealized gains included in earnings for the years ended December 31, 2012, 2011 and 2010, related to commodity derivatives held at December 31, 2012 , 2011 and 2010, totaled $- million, $15 million and $8 million, respectively.

Fair Value, by Balance Sheet Grouping [Table Text Block]

MidAmerican Energy's long-term debt is carried at cost on the Consolidated Financial Statements. The fair value of MidAmerican Energy's long-term debt is a Level 2 fair value measurement and has been estimated based upon quoted market prices, where available, or at the present value of future cash flows discounted at rates consistent with comparable maturities with similar credit risks. The carrying value of MidAmerican Energy's variable-rate long-term debt approximates fair value because of the frequent repricing of these instruments at market rates. The following table presents the carrying value and estimated fair value of MidAmerican Energy's long-term debt as of December 31, (in millions):

	2012				2011
	Carrying Value		Fair Value		Carrying Value		Fair Value
Long-term debt	$	3,259	$	3,737	$	3,115	$	3,620