Risk Management and Hedging Activities (MEC) Balance Sheet Location (Details) (MidAmerican Energy Company and Subsidiaries [Member], Commodity Contract [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010	Dec. 31, 2009
Derivatives, Fair Value [Line Items]
Total derivative, assets (liabilities), net	$ (77)		$ (115)
Cash collateral, net receivable (payable), offset against derivative positions	7		33
Total derivative, net of collateral	(70)		(82)
Current Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Total derivative, assets (liabilities), net	6		25
Cash collateral, net receivable (payable), offset against derivative positions	0		0
Total derivative, net of collateral	6		25
Other Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Total derivative, assets (liabilities), net	1		4
Cash collateral, net receivable (payable), offset against derivative positions	0		0
Total derivative, net of collateral	1		4
Current Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Total derivative, assets (liabilities), net	(61)		(87)
Cash collateral, net receivable (payable), offset against derivative positions	6		28
Total derivative, net of collateral	(55)		(59)
Other Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Total derivative, assets (liabilities), net	(23)		(57)
Cash collateral, net receivable (payable), offset against derivative positions	1		5
Total derivative, net of collateral	(22)		(52)
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	28	[1]	73	[1]
Commodity liability	(73)	[1]	(145)	[1]
Total derivative, assets (liabilities), net	(45)	[1]	(72)	[1]
Net regulatory asset	45		73		27	(14)
Not Designated as Hedging Instrument [Member] | Current Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	18	[1]	60	[1]
Commodity liability	(12)	[1]	(29)	[1]
Total derivative, assets (liabilities), net	6	[1]	31	[1]
Not Designated as Hedging Instrument [Member] | Other Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	1	[1]	6	[1]
Commodity liability	0	[1]	(2)	[1]
Total derivative, assets (liabilities), net	1	[1]	4	[1]
Not Designated as Hedging Instrument [Member] | Current Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	7	[1]	6	[1]
Commodity liability	(47)	[1]	(73)	[1]
Total derivative, assets (liabilities), net	(40)	[1]	(67)	[1]
Not Designated as Hedging Instrument [Member] | Other Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	2	[1]	1	[1]
Commodity liability	(14)	[1]	(41)	[1]
Total derivative, assets (liabilities), net	(12)	[1]	(40)	[1]
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	2		1
Commodity liability	(34)		(44)
Total derivative, assets (liabilities), net	(32)		(43)
Designated as Hedging Instrument [Member] | Current Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	0		0
Commodity liability	0		(6)
Total derivative, assets (liabilities), net	0		(6)
Designated as Hedging Instrument [Member] | Other Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	0		0
Commodity liability	0		0
Total derivative, assets (liabilities), net	0		0
Designated as Hedging Instrument [Member] | Current Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	1		1
Commodity liability	(22)		(21)
Total derivative, assets (liabilities), net	(21)		(20)
Designated as Hedging Instrument [Member] | Other Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	1		0
Commodity liability	(12)		(17)
Total derivative, assets (liabilities), net	$ (11)		$ (17)

[1] MidAmerican Energy's commodity derivatives not designated as hedging contracts are generally included in regulated rates. Accordingly, as of December 31, 2012 and 2011, a net regulatory asset of $45 million and $73 million, respectively, was recorded related to the net derivative liability of $45 million and $72 million, respectively.