Segment Information - MidAmerican Funding (Details) $ in Millions	3 Months Ended							9 Months Ended	12 Months Ended
	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2017 USD ($) OperatingSegments TheNumberOfReportableSegments	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | OperatingSegments									8
Revenues									$ 18,614	$ 17,422	$ 17,880
Operating income (loss)									4,514	4,251	4,328
Interest expense									1,841	1,854	1,904
Income tax (benefit) expense									(554)	403	450
Net income (loss) attributable to parent									2,870	2,542	2,370
Payments to Acquire Property, Plant, and Equipment									4,571	5,090	5,875
Assets	$ 90,208				$ 85,440				90,208	85,440	83,618
Goodwill	9,678				9,010				$ 9,678	9,010	9,076
MidAmerican Funding, LLC and Subsidiaries [Domain]
Segment Reporting Information [Line Items]
Number of Reportable Segments | TheNumberOfReportableSegments									2
Electric Domestic Regulated Revenue									$ 2,108	1,985	1,837
Revenues	676	$ 815	$ 659	$ 696	623	$ 585	$ 626	$ 797	2,846	2,631	2,515
Utilities Operating Expense, Depreciation and Amortization									500	479	407
Operating income (loss)	31	288	136	107	42	140	100	284	562	566	451
Interest expense									237	219	206
Income tax (benefit) expense									(202)	(139)	(150)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									574	532	442
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent									0	0	16
Net income (loss) attributable to parent	(42)	$ 383	$ 131	$ 102	14	$ 127	$ 73	$ 318	574	532	458
Payments to Acquire Property, Plant, and Equipment									1,773	1,636	1,446
Assets	17,621				16,747				17,621	16,747	15,674
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									2,108	1,985	1,837
Utilities Operating Expense, Depreciation and Amortization									458	436	366
Operating income (loss)									485	497	385
Interest expense									196	178	166
Income tax (benefit) expense									(212)	(156)	(163)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									570	512	413
Payments to Acquire Property, Plant, and Equipment									1,686	1,564	1,365
Assets	16,105				15,304				16,105	15,304	14,161
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									719	637	661
Utilities Operating Expense, Depreciation and Amortization									42	43	41
Operating income (loss)									77	68	64
Interest expense									18	18	17
Income tax (benefit) expense									29	22	16
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									35	32	33
Payments to Acquire Property, Plant, and Equipment									87	72	81
Assets	1,482				1,424				1,482	1,424	1,330
Goodwill	79				79				79	79
MidAmerican Funding, LLC and Subsidiaries [Domain] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Other Revenue, Net									19	9	17
Operating income (loss)									0	1	2
Interest expense									23	23	23
Income tax (benefit) expense									(19)	(5)	(3)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									(31)	(12)	(4)
Assets	$ 34				$ 19				$ 34	$ 19	$ 183