Employee Benefit Plans Employee Benefit Plans - PacifiCorp - Employer Contributions (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	$ 7
Employer contributions	6
Domestic Plan [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	39
Employer contributions	34
Domestic Plan [Member] | PacifiCorp [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	4
Employer contributions	$ 3