Income Taxes Income Taxes - MidAmerican Funding - Components of Net Deferred Income Tax Liability (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Deferred Tax Assets and Liabilities [Line Items]
Regulatory liabilities		$ 1,707	$ 909
Derivative contracts		2	29
AROs		223	326
Other		448	707
Total deferred income tax assets, net		3,417	3,103
Property-related items		(9,950)	(14,237)
Regulatory assets		(651)	(1,449)
Other		(215)	(334)
Total deferred income tax liabilities		(11,659)	(16,982)
Net deferred income tax liability		(8,242)	(13,879)
Federal, state and foreign carryforwards		1,118	987
MidAmerican Funding, LLC and Subsidiaries [Domain]
Deferred Tax Assets and Liabilities [Line Items]
Regulatory liabilities		443	333
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits		45	66
AROs		160	230
Other		62	82
Total deferred income tax assets, net		710	711
Property-related items		(2,868)	(3,767)
Regulatory assets		(42)	(471)
Other		(35)	(41)
Total deferred income tax liabilities		(2,945)	(4,279)
Net deferred income tax liability		(2,235)	$ (3,568)
State and Local Jurisdiction [Member]
Deferred Tax Assets and Liabilities [Line Items]
Operating Loss Carryforwards	[1]	10,813
State and Local Jurisdiction [Member] | MidAmerican Funding, LLC and Subsidiaries [Domain]
Deferred Tax Assets and Liabilities [Line Items]
Federal, state and foreign carryforwards		40
Operating Loss Carryforwards		$ 583
Minimum [Member] | MidAmerican Funding, LLC and Subsidiaries [Domain]
Deferred Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Operating Loss and Tax Credit Carry Forwards, Domestic Federal and State, ExpirationDate		2018
Maximum [Member] | MidAmerican Funding, LLC and Subsidiaries [Domain]
Deferred Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Operating Loss and Tax Credit Carry Forwards, Domestic Federal and State, ExpirationDate		2036

[1] The federal net operating loss carryforwards relate principally to net operating loss carryforwards of subsidiaries that are tax residents in both the United States and the United Kingdom. The federal net operating loss carryforwards were generated prior to Berkshire Hathaway Inc.'s ownership and will begin to expire in 2023.