Employee Benefit Plans - MEC (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3	$ 2	$ 7	$ 7
Interest cost	7	7	21	23
Expected return on plan assets	(9)	(10)	(30)	(31)
Net amortization	(3)	(2)	(10)	(9)
Net periodic benefit cost	(2)	(3)	(12)	(10)
MidAmerican Energy Company [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	1	4	4
Interest cost	3	2	7	7
Expected return on plan assets	(3)	(3)	(10)	(10)
Net amortization	(1)	(1)	(3)	(3)
Net periodic benefit cost	1	(1)	(2)	(2)
Domestic Plan [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	6	7	18	22
Interest cost	29	31	87	94
Expected return on plan assets	(40)	(39)	(120)	(120)
Net amortization	7	12	22	36
Net periodic benefit cost	2	11	7	32
Domestic Plan [Member] | MidAmerican Energy Company [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	3	7	8
Interest cost	8	8	23	25
Expected return on plan assets	(11)	(11)	(33)	(33)
Net amortization	0	0	1	1
Net periodic benefit cost	$ (1)	$ 0	$ (2)	$ 1