Employee Benefit Plans Employee Benefit Plans - PacifiCorp (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)
PacifiCorp [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	2	2
Interest cost	3	3	10	11
Expected return on plan assets	(5)	(5)	(16)	(16)
Net amortization	(1)	(1)	(4)	(4)
Net periodic benefit cost	(2)	(2)	(8)	(7)
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] | PacifiCorp [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	1	0	3
Interest cost	12	14	37	41
Expected return on plan assets	(18)	(18)	(54)	(56)
Net amortization	3	8	10	25
Net periodic benefit cost	$ (3)	$ 5	$ (7)	$ 13