Asset Retirement Obligations - MEC - Asset Retirement Obligations By Type (Details) - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Asset Retirement Obligations By Type [Line Items]
Asset Retirement Obligation		$ 954	$ 954	$ 921
Regulatory Liabilities		7,511	3,120
Quad Cities Unit Nos 1 and 2 [Member]
Asset Retirement Obligations By Type [Line Items]
Asset Retirement Obligation		342	343
Fossil Fuel Plant [Member]
Asset Retirement Obligations By Type [Line Items]
Asset Retirement Obligation		380	404
Wind Generating Facility [Member]
Asset Retirement Obligations By Type [Line Items]
Asset Retirement Obligation		138	124
Other Plant in Service [Member]
Asset Retirement Obligations By Type [Line Items]
Asset Retirement Obligation		43	38
MidAmerican Energy Company [Member]
Asset Retirement Obligations By Type [Line Items]
Asset Retirement Obligation		559	567	$ 532
Decommissioning Fund Investments, Fair Value		515	460
MidAmerican Energy Company [Member] | Quad Cities Unit Nos 1 and 2 [Member]
Asset Retirement Obligations By Type [Line Items]
Asset Retirement Obligation		342	343
MidAmerican Energy Company [Member] | Fossil Fuel Plant [Member]
Asset Retirement Obligations By Type [Line Items]
Asset Retirement Obligation		113	132
MidAmerican Energy Company [Member] | Wind Generating Facility [Member]
Asset Retirement Obligations By Type [Line Items]
Asset Retirement Obligation		103	91
MidAmerican Energy Company [Member] | Other Plant in Service [Member]
Asset Retirement Obligations By Type [Line Items]
Asset Retirement Obligation		1	1
Quad Cities Unit Nos 1 and 2 [Member] | MidAmerican Energy Company [Member]
Asset Retirement Obligations By Type [Line Items]
Decommissioning Fund Investments, Fair Value		515	460
Removal Costs [Member]
Asset Retirement Obligations By Type [Line Items]
Regulatory Liabilities	[1]	2,349	2,242
Removal Costs [Member] | MidAmerican Energy Company [Member]
Asset Retirement Obligations By Type [Line Items]
Regulatory Liabilities		$ 688	$ 665

[1] Amounts represent estimated costs, as accrued through depreciation rates and exclusive of ARO liabilities, of removing regulated property, plant and equipment in accordance with accepted regulatory practices. Amounts are deducted from rate base or otherwise accrue a carrying cost.