Segment Information - MidAmerican Funding (Details) $ in Millions	3 Months Ended							9 Months Ended	12 Months Ended
	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2015 USD ($) OperatingSegments TheNumberOfReportableSegments	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | OperatingSegments									8
Revenues									$ 17,880	$ 17,326	$ 12,635
Operating income (loss)									4,328	4,046	2,835
Interest expense									1,904	1,711	1,222
Income tax (benefit) expense									450	589	130
Net income (loss) attributable to parent									2,370	2,095	1,636
Payments to Acquire Property, Plant, and Equipment									5,875	6,555	4,307
Assets	$ 83,618				$ 81,816				83,618	81,816	69,591
Goodwill	9,076				9,343				$ 9,076	9,343	7,527
MidAmerican Funding, LLC and Subsidiaries [Domain]
Segment Reporting Information [Line Items]
Number of Reportable Segments | TheNumberOfReportableSegments									3
Electric Domestic Regulated Revenue									$ 1,837	1,817	1,762
Gas Domestic Regulated Revenue									661	996	824
Other Revenue, Net									922	949	827
Revenues	751	$ 921	$ 797	$ 951	893	$ 775	$ 1,230	$ 864	3,420	3,762	3,413
Utilities Operating Expense, Depreciation and Amortization									407	351	403
Operating income (loss)	33	$ 211	$ 122	$ 107	58	$ 51	$ 153	$ 161	473	423	357
Interest expense									206	197	174
Income tax (benefit) expense									(144)	(110)	(110)
Net income (loss) attributable to parent									458	409	340
Payments to Acquire Property, Plant, and Equipment									1,446	1,526	1,026
Assets	15,674				14,522				15,674	14,522	13,146
Goodwill	1,270				1,270				1,270	1,270
MidAmerican Funding, LLC and Subsidiaries [Domain] | Regulated Electric [Member]
Segment Reporting Information [Line Items]
Electric Domestic Regulated Revenue									1,837	1,817	1,762
Utilities Operating Expense, Depreciation and Amortization									366	312	366
Operating income (loss)									385	319	255
Interest expense									166	157	136
Income tax (benefit) expense									(163)	(138)	(136)
Net income (loss) attributable to parent									413	361	292
Payments to Acquire Property, Plant, and Equipment									1,365	1,429	945
Assets	14,161				13,041				14,161	13,041	11,712
Goodwill	1,191				1,191				1,191	1,191
MidAmerican Funding, LLC and Subsidiaries [Domain] | Regulated Gas [Member]
Segment Reporting Information [Line Items]
Gas Domestic Regulated Revenue									661	996	824
Utilities Operating Expense, Depreciation and Amortization									41	39	37
Operating income (loss)									64	75	74
Interest expense									17	17	15
Income tax (benefit) expense									16	22	23
Net income (loss) attributable to parent									33	40	41
Payments to Acquire Property, Plant, and Equipment									81	97	81
Assets	1,330				1,296				1,330	1,296	1,275
Goodwill	79				79				79	79
MidAmerican Funding, LLC and Subsidiaries [Domain] | Nonregulated Energy [Member]
Segment Reporting Information [Line Items]
Other Revenue, Net									910	927	817
Operating income (loss)									22	28	27
Income tax (benefit) expense									6	12	10
Net income (loss) attributable to parent									16	16	16
Assets	164				167				164	167	131
MidAmerican Funding, LLC and Subsidiaries [Domain] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Other Revenue, Net									12	22	10
Operating income (loss)									2	1	1
Interest expense									23	23	23
Income tax (benefit) expense									(3)	(6)	(7)
Net income (loss) attributable to parent									(4)	(8)	(9)
Assets	$ 19				$ 18				$ 19	$ 18	$ 28