Employee Benefit Plans - MEC (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Pension Plan [Member] | Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5	$ 6	$ 10	$ 12
Interest cost	26	29	52	58
Expected return on plan assets	(41)	(40)	(82)	(80)
Net amortization	7	8	15	15
Net periodic benefit cost	(3)	3	(5)	5
Pension Plan [Member] | Domestic Plan [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	3	4	5
Interest cost	7	7	14	15
Expected return on plan assets	(11)	(11)	(22)	(22)
Net amortization	0	1	1	1
Net periodic benefit cost	(2)	0	(3)	(1)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	2	5	4
Interest cost	6	8	12	14
Expected return on plan assets	(12)	(11)	(22)	(21)
Net amortization	(3)	(4)	(6)	(7)
Net periodic benefit cost	(6)	(5)	(11)	(10)
Other Postretirement Benefits Plan [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	1	3	2
Interest cost	2	2	4	4
Expected return on plan assets	(4)	(4)	(7)	(7)
Net amortization	(1)	(1)	(2)	(2)
Net periodic benefit cost	(1)	$ (2)	(2)	$ (3)
Accounting Standards Update 2017-07 [Member] | Other Pension, Postretirement and Supplemental Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior Period Reclassification Adjustment	4		8
Accounting Standards Update 2017-07 [Member] | Other Pension, Postretirement and Supplemental Plans [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior Period Reclassification Adjustment	(6)		(11)
Accounting Standards Update 2017-07 [Member] | MidAmerican Energy Company [Member] | Other Pension, Postretirement and Supplemental Plans [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior Period Reclassification Adjustment	$ (5)		$ (10)