Unaudited Quarterly Operating Results - MidAmerican Funding (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 Funding, LLC and Subsidiaries [Domain]
Quarterly Operating Results [Line Items]
Revenues	$ 751	$ 921	$ 797	$ 951	$ 893	$ 775	$ 1,230	$ 864	3,420	3,762	3,413
Operating income (loss)	33	211	122	107	58	51	153	161	473	423	357
Net income	$ (1)	$ 231	$ 129	$ 99	$ 56	$ 30	$ 155	$ 168	$ 458	$ 409	$ 341