Risk Management and Hedging Activities - MEC - Designated as Hedging Activities (Details) - Designated as Hedging Instrument [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive (Income) Loss, Net, Derivatives [Roll Forward]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ (36)
Commodity Contract [Member]
Accumulated Other Comprehensive (Income) Loss, Net, Derivatives [Roll Forward]
Beginning balance	32	$ 12	$ 32
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	52	(6)	(9)
Ending balance	46	32	12
Commodity Contract [Member] | MidAmerican Energy Company [Member]
Accumulated Other Comprehensive (Income) Loss, Net, Derivatives [Roll Forward]
Beginning balance	34	11	32
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	58	(3)	(11)
Cash Flow Hedge Gain (Loss) Reclassified To Cost Of Sales Nonregulated	(47)	26	(10)
Ending balance	45	34	11
Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net	(1)	$ (2)	$ 0
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ 32