Consolidated Statements of Comprehensive Income (Parenthetical) - MEC - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Unrealized (losses) gains on available-for-sale securities, tax	$ 22	$ 113
Unrealized (losses) gains on cash flow hedges, tax	(14)	1
MidAmerican Energy Company [Member]
Unrealized (losses) gains on available-for-sale securities, tax	0	0
Unrealized (losses) gains on cash flow hedges, tax	$ 0	$ 2

Amount of tax expense (benefit), after reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669646-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e640-108580

Name:	us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration