Unaudited Quarterly Operating Results - MEC (Details) - USD ($) $ in Millions	3 Months Ended							9 Months Ended	12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Operating Results [Line Items]
Revenues									$ 17,880	$ 17,326	$ 12,635
Operating income (loss)									4,328	4,046	2,835
Net income									2,400	2,122	1,676
MidAmerican Energy Company [Member]
Quarterly Operating Results [Line Items]
Revenues	$ 748	$ 920	$ 793	$ 946	$ 884	$ 769	$ 1,225	$ 862	3,407	3,740	3,403
Operating income (loss)	33	210	122	106	58	51	153	160	471	422	356
Net income	$ 3	$ 234	$ 131	$ 94	$ 58	$ 32	$ 157	$ 170	$ 462	$ 417	$ 350