Segment Information (MEC) (Details) (MidAmerican Energy Company [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 ReportableSegments	Mar. 31, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Number of Reportable Segments	3
Regulated electric	$ 415	$ 380
Regulated gas	315	263
Nonregulated energy	190	231
Total operating revenue	920	874
Depreciation and amortization	107	93
Total operating income	106	92
Assets	11,056		11,232
Regulated electric [Member]
Segment Reporting Information [Line Items]
Regulated electric	415	380
Depreciation and amortization	98	84
Total operating income	50	48
Assets	9,837		9,898
Regulated gas [Member]
Segment Reporting Information [Line Items]
Regulated gas	315	263
Depreciation and amortization	9	9
Total operating income	45	30
Assets	1,106		1,202
Nonregulated energy [Member]
Segment Reporting Information [Line Items]
Nonregulated energy	190	231
Total operating income	11	14
Assets	$ 113		$ 132