Employee Benefit Plans - MEC (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Domestic Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 8	$ 8
Interest cost	31	30
Expected return on plan assets	(40)	(42)
Net amortization	11	13
Net periodic benefit cost	10	9
Domestic Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	4
Interest cost	8	7
Expected return on plan assets	(11)	(12)
Net amortization	(3)	(3)
Net periodic benefit cost	(3)	(4)
MidAmerican Energy Company [Member] | Domestic Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	3
Interest cost	8	8
Expected return on plan assets	(11)	(11)
Net periodic benefit cost	0	0
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2
Interest cost	2	2
Expected return on plan assets	(3)	(4)
Net amortization	(1)	(1)
Net periodic benefit cost	$ (1)	$ (1)