Jointly Owned Utility Facilities (MEC) (Details) (MidAmerican Energy Company and Subsidiaries [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 3,176
Accumulated Depreciation and Amortization	1,494
Construction Work in Progress	270
Louisa Unit No. 1 [Member]
Jointly Owned Utility Plant Interests [Line Items]
Company Share	88.00%
Plant in Service	738
Accumulated Depreciation and Amortization	368
Construction Work in Progress	1
Quad Cities Unit Nos. 1 & 2 [Member]
Jointly Owned Utility Plant Interests [Line Items]
Company Share	25.00%	[1]
Plant in Service	595	[1]
Accumulated Depreciation and Amortization	272	[1]
Construction Work in Progress	37	[1]
Walter Scott, Jr. Unit No. 3 [Member]
Jointly Owned Utility Plant Interests [Line Items]
Company Share	79.10%
Plant in Service	542
Accumulated Depreciation and Amortization	269
Construction Work in Progress	1
Walter Scott, Jr. Unit No. 4 [Member]
Jointly Owned Utility Plant Interests [Line Items]
Company Share	59.70%	[2]
Plant in Service	437	[2]
Accumulated Depreciation and Amortization	65	[2]
Construction Work in Progress	1	[2]
Revenue Sharing Credits Netted Against Facility In Service	319
Revenue Sharing Credits Netted Against Accumulated Depreciation	46
Ottumwa Unit No. 1 [Member]
Jointly Owned Utility Plant Interests [Line Items]
Company Share	52.00%
Plant in Service	274
Accumulated Depreciation and Amortization	166
Construction Work in Progress	88
George Neal Unit No. 3 [Member]
Jointly Owned Utility Plant Interests [Line Items]
Company Share	72.00%
Plant in Service	181
Accumulated Depreciation and Amortization	136
Construction Work in Progress	71
George Neal Unit No. 4 [Member]
Jointly Owned Utility Plant Interests [Line Items]
Company Share	40.60%
Plant in Service	171
Accumulated Depreciation and Amortization	143
Construction Work in Progress	71
Transmission facilities [Member]
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	238	[3]
Accumulated Depreciation and Amortization	75	[3]
Construction Work in Progress	$ 0	[3]
Jointly Owned Utility Plant Proportionate Ownership Percentage Share	Various	[3]

[1] Includes amounts related to nuclear fuel.

[2] Plant in service and accumulated depreciation and amortization amounts are net of credits applied under Iowa revenue sharing arrangements totaling $319 million and $46 million, respectively.

[3] Includes 345 and 161 kilovolt transmission lines and substations.