Risk Management and Hedging Activities Risk Management and Hedging Activities - MEC - Not Designated as Hedging Contracts (Details) - Commodity Contract [Member] - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Regulatory Assets (Liabilities), Net, Derivatives [Roll Forward]
Beginning balance	$ 148	$ 250	$ 223
Changes In Fair Value Derivatives Recognized In Regulatory Assets Or Liabilities, Net	53	(30)	128
Net Gains (Losses) Reclassified To Operating Revenue	10	(5)	1
Ending balance	119	148	250
MidAmerican Energy Company [Member]
Regulatory Assets (Liabilities), Net, Derivatives [Roll Forward]
Beginning balance	(4)	20	38
Changes In Fair Value Derivatives Recognized In Regulatory Assets Or Liabilities, Net	16	3	40
Net Gains (Losses) Reclassified To Operating Revenue	1	(15)	(42)
Net Gains (Losses) Reclassified To Cost Of Domestic Regulated Electric	(4)	0	(1)
Net Gains (Losses) Reclassified To Cost Of Natural Gas Purchases	(6)	(12)	(15)
Ending balance	3	(4)	20
Derivative, Gain (Loss) on Derivative, Net	0	0	(4)
Other Revenue Net [Member] | MidAmerican Energy Company [Member]
Regulatory Assets (Liabilities), Net, Derivatives [Roll Forward]
Derivative, Gain (Loss) on Derivative, Net	0	0	15
Cost Of Natural Gas [Member] | MidAmerican Energy Company [Member]
Regulatory Assets (Liabilities), Net, Derivatives [Roll Forward]
Derivative, Gain (Loss) on Derivative, Net	0	0	2
Cost Of Sales Nonregulated [Member] | MidAmerican Energy Company [Member]
Regulatory Assets (Liabilities), Net, Derivatives [Roll Forward]
Derivative, Gain (Loss) on Derivative, Net	$ 0	$ 0	$ (21)