Fair Value Measurements (MEC) (Details) (MidAmerican Energy Company [Member], USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Collateral and netting [Member]
Assets, Fair Value Disclosure [Abstract]
Cash Collateral, Net Receivable (Payable), Offset Against Derivative Positions	$ 38		$ 0
Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Commodity derivative assets	24		2
Assets, Fair Value Disclosure	556		513
Liabilities - commodity derivatives, fair value	(6)		(29)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Commodity derivative assets	3		3
Assets, Fair Value Disclosure	467		450
Liabilities - commodity derivatives, fair value	(1)		(1)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Commodity derivative assets	53		16
Assets, Fair Value Disclosure	96		57
Liabilities - commodity derivatives, fair value	(73)		(42)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Commodity derivative assets	16		6
Assets, Fair Value Disclosure	41		29
Liabilities - commodity derivatives, fair value	(18)		(9)
Fair Value, Measurements, Recurring [Member] | Collateral and netting [Member]
Assets, Fair Value Disclosure [Abstract]
Commodity derivative assets	(48)	[1]	(23)	[1]
Assets, Fair Value Disclosure	(48)	[1]	(23)	[1]
Liabilities - commodity derivatives, fair value	86	[1]	23	[1]
Money market mutual funds [Member] | Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	98	[2]	95	[2]
Money market mutual funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	98	[2]	95	[2]
Money market mutual funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	[2]	0	[2]
Money market mutual funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	[2]	0	[2]
Money market mutual funds [Member] | Fair Value, Measurements, Recurring [Member] | Collateral and netting [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	[1],[2]	0	[1],[2]
United States government obligations [Member] | Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	135		134
United States government obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	135		134
United States government obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
United States government obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
United States government obligations [Member] | Fair Value, Measurements, Recurring [Member] | Collateral and netting [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	[1]	0	[1]
International government obligations [Member] | Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	1		1
International government obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
International government obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	1		1
International government obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
International government obligations [Member] | Fair Value, Measurements, Recurring [Member] | Collateral and netting [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	[1]	0	[1]
Corporate obligations [Member] | Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	38		36
Corporate obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
Corporate obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	38		36
Corporate obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
Corporate obligations [Member] | Fair Value, Measurements, Recurring [Member] | Collateral and netting [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	[1]	0	[1]
Municipal obligations [Member] | Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	2		2
Municipal obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
Municipal obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	2		2
Municipal obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
Municipal obligations [Member] | Fair Value, Measurements, Recurring [Member] | Collateral and netting [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	[1]	0	[1]
Agency, asset and mortgage-backed obligations [Member] | Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	2		2
Agency, asset and mortgage-backed obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
Agency, asset and mortgage-backed obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	2		2
Agency, asset and mortgage-backed obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
Agency, asset and mortgage-backed obligations [Member] | Fair Value, Measurements, Recurring [Member] | Collateral and netting [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	[1]	0	[1]
Auction rate securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	25		23
Auction rate securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
Auction rate securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
Auction rate securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	25		23
Auction rate securities [Member] | Fair Value, Measurements, Recurring [Member] | Collateral and netting [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	[1]	0	[1]
United States equity securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	226		214
United States equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	226		214
United States equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
United States equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
United States equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Collateral and netting [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	[1]	0	[1]
International equity securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	5		4
International equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	5		4
International equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
International equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0		0
International equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Collateral and netting [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	$ 0	[1]	$ 0	[1]

[1] Represents netting under master netting arrangements and a net cash collateral receivable of $38 million and $- million as of June 30, 2014 and December 31, 2013, respectively.

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