Employee Benefit Plans Employee Benefit Plans - PacifiCorp (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)
PacifiCorp [Member] | Domestic Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest cost	14	13
Expected return on plan assets	(19)	(19)
Net amortization	8	10
Net periodic benefit cost	4	5
PacifiCorp [Member] | Domestic Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest cost	4	4
Expected return on plan assets	(6)	(6)
Net amortization	(1)	(1)
Net periodic benefit cost	$ (2)	$ (2)