Employee Benefit Plans - PacifiCorp - Contributions and Benefit Payments (Details) $ in Millions	Dec. 31, 2017 USD ($)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	$ 3
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	54
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	55
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	57
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	55
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	54
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	243
Other Postretirement Benefits Plan [Member] | PacifiCorp [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	0
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	25
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	25
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	26
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	23
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	23
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	100
Domestic Plan [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	39
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	226
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	224
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	224
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	222
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	214
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	979
Domestic Plan [Member] | Pension Plan [Member] | PacifiCorp [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	4
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	108
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	107
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	103
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	99
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	94
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	$ 393