Risk Management and Hedging Activities (MEC) Balance Sheet Location (Details) (MidAmerican Energy Company [Member], Commodity Contract [Member], USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Jun. 30, 2014	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Total derivative assets (liabilities), net	$ (40)			$ (27)
Cash collateral, net receivable (payable), offset against derivatives	38			0
Total derivatives - net of collateral	(2)			(27)
Current Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Total derivative assets (liabilities), net	10			2
Cash collateral, net receivable (payable), offset against derivatives	0			(2)
Total derivatives - net of collateral	10			0
Other Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Total derivative assets (liabilities), net	1			2
Cash collateral, net receivable (payable), offset against derivatives	0			0
Total derivatives - net of collateral	1			2
Current Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Total derivative assets (liabilities), net	(45)			(20)
Cash collateral, net receivable (payable), offset against derivatives	36			1
Total derivatives - net of collateral	(9)			(19)
Other Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Total derivative assets (liabilities), net	(6)			(11)
Cash collateral, net receivable (payable), offset against derivatives	2			1
Total derivatives - net of collateral	(4)			(10)
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	29	[1]		23	[1]
Commodity liabilities	(79)	[1]		(40)	[1]
Total derivative assets (liabilities), net	(50)	[1]		(17)	[1]
Net regulatory asset	51		48	10		20	23	45
Not Designated as Hedging Instrument [Member] | Current Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	3	[1]		3	[1]
Commodity liabilities	(2)	[1]		(1)	[1]
Total derivative assets (liabilities), net	1	[1]		2	[1]
Not Designated as Hedging Instrument [Member] | Other Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	1	[1]		3	[1]
Commodity liabilities	0	[1]		(1)	[1]
Total derivative assets (liabilities), net	1	[1]		2	[1]
Not Designated as Hedging Instrument [Member] | Current Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	25	[1]		16	[1]
Commodity liabilities	(75)	[1]		(32)	[1]
Total derivative assets (liabilities), net	(50)	[1]		(16)	[1]
Not Designated as Hedging Instrument [Member] | Other Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	0	[1]		1	[1]
Commodity liabilities	(2)	[1]		(6)	[1]
Total derivative assets (liabilities), net	(2)	[1]		(5)	[1]
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	25			2
Commodity liabilities	(15)			(12)
Total derivative assets (liabilities), net	10			(10)
Designated as Hedging Instrument [Member] | Current Assets - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	14			1
Commodity liabilities	(5)			(1)
Total derivative assets (liabilities), net	9			0
Designated as Hedging Instrument [Member] | Other 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] | Current Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	6			1
Commodity liabilities	(1)			(5)
Total derivative assets (liabilities), net	5			(4)
Designated as Hedging Instrument [Member] | Other Liabilities - Other [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	5			0
Commodity liabilities	(9)			(6)
Total derivative assets (liabilities), net	$ (4)			$ (6)

[1] MidAmerican Energy's commodity derivatives not designated as hedging contracts are generally included in regulated rates, and as of September 30, 2014 and December 31, 2013, a net regulatory asset of $51 million and $10 million, respectively, was recorded related to the net derivative liability of $50 million and $17 million, respectively.