Commitments and Contingencies - Commitments Table (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) number_of_projects	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Contractual Obligation [Line Items]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 197
Operating Leases, Future Minimum Payments, Due in Two Years	177
Operating Leases, Future Minimum Payments, Due in Three Years	160
Operating Leases, Future Minimum Payments, Due in Four Years	139
Operating Leases, Future Minimum Payments, Due in Five Years	111
Operating Leases, Future Minimum Payments, Due Thereafter	1,738
Operating Leases, Future Minimum Payments Due	2,522
Contractual Obligation, Due in Next Twelve Months	5,048
Contractual Obligation, Due in Second Year	2,767
Contractual Obligation, Due in Third Year	1,895
Contractual Obligation, Due in Fourth Year	1,590
Contractual Obligation, Due in Fifth Year	1,399
Contractual Obligation, Due after Fifth Year	14,251
Contractual Obligation	26,950
Operating Leases, Rent Expense	191	$ 156	$ 156
MidAmerican Funding [Member]
Contractual Obligation [Line Items]
Coal transportation costs, railroad	$ 111	$ 109	$ 137
Number of Construction Projects | number_of_projects	4
Fuel, capacity and transmission contract commitments [Member]
Contractual Obligation [Line Items]
Purchase Obligation, Due in Next Twelve Months	$ 2,215
Purchase Obligation, Due in Second Year	1,659
Purchase Obligation, Due in Third Year	1,380
Purchase Obligation, Due in Fourth Year	1,174
Purchase Obligation, Due in Fifth Year	1,047
Purchase Obligation, Due after Fifth Year	11,155
Purchase Obligation	18,630
Capital Addition Purchase Commitments [Member]
Contractual Obligation [Line Items]
Purchase Obligation, Due in Next Twelve Months	2,330
Purchase Obligation, Due in Second Year	587
Purchase Obligation, Due in Third Year	52
Purchase Obligation, Due in Fourth Year	0
Purchase Obligation, Due in Fifth Year	0
Purchase Obligation, Due after Fifth Year	0
Purchase Obligation	2,969
Maintenance, service and other contracts [Member]
Contractual Obligation [Line Items]
Purchase Obligation, Due in Next Twelve Months	306
Purchase Obligation, Due in Second Year	344
Purchase Obligation, Due in Third Year	303
Purchase Obligation, Due in Fourth Year	277
Purchase Obligation, Due in Fifth Year	241
Purchase Obligation, Due after Fifth Year	1,358
Purchase Obligation	$ 2,829