Employee Benefit Plans - MEC (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Other Pension, Postretirement and Supplemental Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior Period Reclassification Adjustment	$ 4
Other Pension, Postretirement and Supplemental Plans [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior Period Reclassification Adjustment	5
Pension Plan [Member] | Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	$ 6
Interest cost	26	29
Expected return on plan assets	(41)	(40)
Net amortization	8	7
Net periodic benefit cost	(2)	2
Pension Plan [Member] | Domestic Plan [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2
Interest cost	7	8
Expected return on plan assets	(11)	(11)
Net amortization	1	0
Net periodic benefit cost	(1)	(1)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2
Interest cost	6	6
Expected return on plan assets	(10)	(10)
Net amortization	(3)	(3)
Net periodic benefit cost	(5)	(5)
Other Postretirement Benefits Plan [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest cost	2	2
Expected return on plan assets	(3)	(3)
Net amortization	(1)	(1)
Net periodic benefit cost	$ (1)	$ (1)