Commitments and Contingencies - Commitments Table (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) number_of_projects	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Contractual Obligation [Line Items]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 141
Operating Leases, Future Minimum Payments, Due in Two Years	122
Operating Leases, Future Minimum Payments, Due in Three Years	101
Operating Leases, Future Minimum Payments, Due in Four Years	87
Operating Leases, Future Minimum Payments, Due in Five Years	73
Operating Leases, Future Minimum Payments, Due Thereafter	1,085
Operating Leases, Future Minimum Payments Due	1,609
Contractual Obligation, Due in Next Twelve Months	3,666
Contractual Obligation, Due in Second Year	1,997
Contractual Obligation, Due in Third Year	1,768
Contractual Obligation, Due in Fourth Year	1,482
Contractual Obligation, Due in Fifth Year	1,264
Contractual Obligation, Due after Fifth Year	11,865
Contractual Obligation	22,042
Operating Leases, Rent Expense	156	$ 161	$ 146
MidAmerican Funding [Member]
Contractual Obligation [Line Items]
Coal transportation costs, railroad	$ 137	$ 185	$ 159
Number of Construction Projects | number_of_projects	2
Fuel, capacity and transmission contract commitments [Member]
Contractual Obligation [Line Items]
Purchase Obligation, Due in Next Twelve Months	$ 2,370
Purchase Obligation, Due in Second Year	1,606
Purchase Obligation, Due in Third Year	1,389
Purchase Obligation, Due in Fourth Year	1,208
Purchase Obligation, Due in Fifth Year	1,010
Purchase Obligation, Due after Fifth Year	10,053
Purchase Obligation	17,636
Capital Addition Purchase Commitments [Member]
Contractual Obligation [Line Items]
Purchase Obligation, Due in Next Twelve Months	852
Purchase Obligation, Due in Second Year	49
Purchase Obligation, Due in Third Year	66
Purchase Obligation, Due in Fourth Year	1
Purchase Obligation, Due in Fifth Year	1
Purchase Obligation, Due after Fifth Year	4
Purchase Obligation	973
Maintenance, service and other contracts [Member]
Contractual Obligation [Line Items]
Purchase Obligation, Due in Next Twelve Months	303
Purchase Obligation, Due in Second Year	220
Purchase Obligation, Due in Third Year	212
Purchase Obligation, Due in Fourth Year	186
Purchase Obligation, Due in Fifth Year	180
Purchase Obligation, Due after Fifth Year	723
Purchase Obligation	$ 1,824