Employee Benefit Plans - MEC (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Domestic Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 6	$ 8
Interest cost	29	31
Expected return on plan assets	(40)	(40)
Net amortization	7	11
Net periodic benefit cost	2	10
Domestic Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	3
Interest cost	6	8
Expected return on plan assets	(10)	(11)
Net amortization	(3)	(3)
Net periodic benefit cost	(5)	(3)
MidAmerican Energy Company [Member] | Domestic Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	3
Interest cost	8	8
Expected return on plan assets	(11)	(11)
Net periodic benefit cost	(1)	0
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [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)