Employee Benefit Plans (MEC) Fair Value Measurements (Details) (MidAmerican Energy Company and Subsidiaries [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010	Dec. 31, 2009
United States Pension Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 643		$ 555		$ 546
United States Pension Plans of US Entity, Defined Benefit [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	257	[1]	197	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	360	[1]	334	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	26	[1]	24	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	7		9
United States Pension Plans of US Entity, Defined Benefit [Member] | Cash Equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	7	[1]	9	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Cash Equivalents [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | United States government obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	19		6
United States Pension Plans of US Entity, Defined Benefit [Member] | United States government obligations [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	19	[1]	6	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | United States government obligations [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | United States government obligations [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	31		29
United States Pension Plans of US Entity, Defined Benefit [Member] | Corporate Debt Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Corporate Debt Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	31	[1]	29	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Corporate Debt Securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Municipal obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	5		5
United States Pension Plans of US Entity, Defined Benefit [Member] | Municipal obligations [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Municipal obligations [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	5	[1]	5	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Municipal obligations [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Agency, asset and mortgage-backed obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	29		35
United States Pension Plans of US Entity, Defined Benefit [Member] | Agency, asset and mortgage-backed obligations [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Agency, asset and mortgage-backed obligations [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	29	[1]	35	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Agency, asset and mortgage-backed obligations [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | United States companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	137		115
United States Pension Plans of US Entity, Defined Benefit [Member] | United States companies [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	137	[1]	115	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | United States companies [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | United States companies [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	389	[2]	332	[2]
Percentage of Investment Funds Comprised Of Equity Securitites	74.00%		77.00%
Percentage of Investment Funds Comprised Of Debt Securities	26.00%		23.00%
Percentage Of Investment Funds Invested in United States Securities	77.00%		79.00%
Percentage Of Investment Funds Invested In International Securities	23.00%		21.00%
United States Pension Plans of US Entity, Defined Benefit [Member] | Equity Funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	101	[1],[2]	76	[1],[2]
United States Pension Plans of US Entity, Defined Benefit [Member] | Equity Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	288	[1],[2]	256	[1],[2]
United States Pension Plans of US Entity, Defined Benefit [Member] | Equity Funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1],[2]	0	[1],[2]
United States Pension Plans of US Entity, Defined Benefit [Member] | Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	26		24
United States Pension Plans of US Entity, Defined Benefit [Member] | Real Estate Funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Real Estate Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | Real Estate Funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	26	[1]	24	[1]	17	15
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	226		213		216
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	171		164
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	55		49
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	2		6
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Cash Equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	2		6
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Cash Equivalents [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | United States government obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	4		6
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | United States government obligations [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	4		6
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | United States government obligations [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | United States government obligations [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	9		7
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Corporate Debt Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Corporate Debt Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	9		7
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Corporate Debt Securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Municipal obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	32		30
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Municipal obligations [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Municipal obligations [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	32		30
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Municipal obligations [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Agency, asset and mortgage-backed obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	14		12
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Agency, asset and mortgage-backed obligations [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Agency, asset and mortgage-backed obligations [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	14		12
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Agency, asset and mortgage-backed obligations [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | United States companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	102		88
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | United States companies [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	102		88
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | United States companies [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | United States companies [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	63		64
Percentage of Investment Funds Comprised Of Equity Securitites	86.00%		83.00%
Percentage of Investment Funds Comprised Of Debt Securities	14.00%		17.00%
Percentage Of Investment Funds Invested in United States Securities	51.00%		59.00%
Percentage Of Investment Funds Invested In International Securities	49.00%		41.00%
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Equity Funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	63		64
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Equity Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | Equity Funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 0		$ 0

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

[2] (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.