Income Taxes - MEC - Summary of Operating Loss Carryforwards (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Federal, state and foreign carryforwards		$ 1,118	$ 987
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	[1]	10,813
MidAmerican Energy Company [Member] | State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Federal, state and foreign carryforwards		40
Operating Loss Carryforwards		$ 583
MidAmerican Energy Company [Member] | Minimum [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss and Tax Credit Carry Forwards, Domestic Federal and State, ExpirationDate		2018
MidAmerican Energy Company [Member] | Maximum [Member]
Operating Loss Carryforwards [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.