Summary of Significant Accounting Policies (MEC) Utility Plant, Net - General (Details) (MidAmerican Energy Company [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Regulated electric [Member]
Notes to Financial Statements [Line Items]
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	2.80%	3.30%	3.30%
Regulated gas [Member]
Notes to Financial Statements [Line Items]
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	2.80%	2.80%	2.80%
Service Life [Member]
Notes to Financial Statements [Line Items]
Change in Accounting Estimates, Impact on Period of Change	50		5
Change in Accounting Estimates, Impact on Future Periods			11
Electricity Generation Plant, Non-Nuclear [Member]
Notes to Financial Statements [Line Items]
Change in Accounting Estimates, Impact on Period of Change		20
Change in Accounting Estimates, Impact on Future Periods		49