Components of Accumulated Other Comprehensive Income (Loss), Net (MEC) (Details) (MidAmerican Energy Company [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other comprehensive income, unrealized gains on available-for-sales securities	$ 0	$ 1
Other comprehensive income, unrealized gains on cash flow hedges	2	14
Other comprehensive income (loss)	2	15
Accumulated Other Comprehensive Income (Loss), Net [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance, Unrealized Losses on Available-For-Sale Securities	(3)	(4)
Beginning Balance, Unrealized (Losses) Gains on Cash Flow Hedges	(20)	(7)
Beginning Balance, Accumulated Other Comprehensive Income (Loss), Net	(23)	(11)
Other comprehensive income, unrealized gains on available-for-sales securities	0	1
Other comprehensive income, unrealized gains on cash flow hedges	2	14
Other comprehensive income (loss)	2	15
Ending Balance, Unrealized Losses on Available-For-Sale Securities	(3)	(3)
Ending Balance, Unrealized (Losses) Gains on Cash Flow Hedges	(18)	7
Ending Balance, Accumulated Other Comprehensive Income (Loss), Net	$ (21)	$ 4