Risk Management and Hedging Activities (MEC) Balance Sheet Location (Details) (MidAmerican Energy Company [Member], Commodity Contract [Member], USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Mar. 31, 2013	Dec. 31, 2012		Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Total derivative assets (liabilities), net	$ (50)			$ (77)
Cash collateral, net receivable (payable), offset against derivatives	2			7
Total derivatives - net of collateral	(48)			(70)
Current Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Total derivative assets (liabilities), net	3			6
Cash collateral, net receivable (payable), offset against derivatives	0			0
Total derivatives - net of collateral	3			6
Other Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Total derivative assets (liabilities), net	1			1
Cash collateral, net receivable (payable), offset against derivatives	0			0
Total derivatives - net of collateral	1			1
Current Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Total derivative assets (liabilities), net	(42)			(61)
Cash collateral, net receivable (payable), offset against derivatives	2			6
Total derivatives - net of collateral	(40)			(55)
Other Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Total derivative assets (liabilities), net	(12)			(23)
Cash collateral, net receivable (payable), offset against derivatives	0			1
Total derivatives - net of collateral	(12)			(22)
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	26	[1]		28	[1]
Commodity liabilities	(50)	[1]		(73)	[1]
Total derivative assets (liabilities), net	(24)	[1]		(45)	[1]
Net regulatory asset	23		24	45		63	60	73
Not Designated as Hedging Instrument [Member] | Current Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	18	[1]		18	[1]
Commodity liabilities	(15)	[1]		(12)	[1]
Total derivative assets (liabilities), net	3	[1]		6	[1]
Not Designated as Hedging Instrument [Member] | Other Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	3	[1]		1	[1]
Commodity liabilities	(1)	[1]		0	[1]
Total derivative assets (liabilities), net	2	[1]		1	[1]
Not Designated as Hedging Instrument [Member] | Current Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	5	[1]		7	[1]
Commodity liabilities	(31)	[1]		(47)	[1]
Total derivative assets (liabilities), net	(26)	[1]		(40)	[1]
Not Designated as Hedging Instrument [Member] | Other Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	0	[1]		2	[1]
Commodity liabilities	(3)	[1]		(14)	[1]
Total derivative assets (liabilities), net	(3)	[1]		(12)	[1]
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	2			2
Commodity liabilities	(28)			(34)
Total derivative assets (liabilities), net	(26)			(32)
Designated as Hedging Instrument [Member] | Current Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	0			0
Commodity liabilities	0			0
Total derivative assets (liabilities), net	0			0
Designated as Hedging Instrument [Member] | Other Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	(1)			0
Commodity liabilities	0			0
Total derivative assets (liabilities), net	(1)			0
Designated as Hedging Instrument [Member] | Current Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	2			1
Commodity liabilities	(18)			(22)
Total derivative assets (liabilities), net	(16)			(21)
Designated as Hedging Instrument [Member] | Other Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	1			1
Commodity liabilities	(10)			(12)
Total derivative assets (liabilities), net	$ (9)			$ (11)

[1] MidAmerican Energy's commodity derivatives not designated as hedging contracts are generally included in regulated rates, and as of June 30, 2013 and December 31, 2012, a net regulatory asset of $23 million and $45 million, respectively, was recorded related to the net derivative liability of $24 million and $45 million, respectively.