Risk Management and Hedging Activities - MEC - Designated as Hedging Contracts (Details) - Commodity derivative [Member] - Designated as Hedging Instrument [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive (Income) Loss, Net, Derivatives [Roll Forward]
Accumulated other comprehensive income (loss), net, cummulative net gain (loss) from cash flow hedges, effect before taxes	$ (72)	$ (27)	$ (46)	$ (32)
Changes in fair value recognized in OCI	(28)	25	20	17
Accumulated other comprehensive income (loss), net, cummulative net gain (loss) from cash flow hedges, effect before taxes	(26)	(38)	(26)	(38)
MidAmerican Energy Company [Member]
Accumulated Other Comprehensive (Income) Loss, Net, Derivatives [Roll Forward]
Accumulated other comprehensive income (loss), net, cummulative net gain (loss) from cash flow hedges, effect before taxes	0	(30)	(45)	(34)
Cumulative Net Gain (Loss) From Cash Flow Hedges, Before Taxes Transferred to Affiliate	0	0	(45)	0
Changes in fair value recognized in OCI	0	25	0	19
Cash Flow Hedge Gain (Loss) Reclassified To Cost Of Sales Nonregulated	0	(16)	0	(14)
Accumulated other comprehensive income (loss), net, cummulative net gain (loss) from cash flow hedges, effect before taxes	$ 0	$ (39)	$ 0	$ (39)