Employee Benefit Plans - Plan Assumptions (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year	6.80%	7.10%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate	5.00%	5.00%
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate	2025	2025
Pension Plan [Member] | UNITED KINGDOM
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.90%	2.60%	2.70%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	3.55%	3.45%	3.00%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Expected Rate Of Future Price Inflation	3.05%	2.95%	3.00%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	2.60%	2.70%	3.70%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	4.90%	5.00%	5.60%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase	3.45%	3.00%	2.90%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Rate of Future Price Inflation	2.95%	3.00%	2.90%
Pension Plan [Member] | Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.25%	3.60%	4.06%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	2.75%	2.75%	2.75%
Interest Crediting Rates for Cash Balance Plan, First Year	3.38%	2.49%	2.57%
Interest Crediting Rates for Cash Balance Plan, Third Year	3.54%	3.06%	2.57%
Interest Crediting Rates for Cash Balance Plan, Fourth Year	3.56%	2.72%	3.01%
Interest Crediting Rates for Cash Balance Plan, Fifth Year		2.72%	3.01%
Interest Crediting Rates for Cash Balance Plan, Sixth Year			3.01%
Interest Crediting Rates for Cash Balance Plan, Second Year	3.54%	3.06%	2.57%
Interest crediting rates for cash balance plan	3.38%	2.49%	2.57%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	3.60%	4.06%	4.43%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	6.36%	6.55%	6.78%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase	2.75%	2.75%	2.75%
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.21%	3.57%	4.01%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	3.57%	4.01%	4.33%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	6.44%	6.73%	7.03%
PacifiCorp [Member] | Pension Plan [Member] | Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.25%	3.60%	4.05%
Interest Crediting Rates for Cash Balance Plan, Fourth Year	3.25%
Interest crediting rates for cash balance plan	3.40%	1.61%	2.06%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	3.60%	4.05%	4.40%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	7.00%	7.25%	7.50%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase			2.75%
PacifiCorp [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.25%	3.60%	4.05%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	3.60%	4.05%	4.35%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	6.86%	7.25%	7.50%
Nonunion pension plan participant [Member] | PacifiCorp [Member] | Pension Plan [Member] | Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest Crediting Rates for Cash Balance Plan, Third Year		2.26%	1.44%
Interest Crediting Rates for Cash Balance Plan, Fourth Year		1.60%	2.05%
Interest Crediting Rates for Cash Balance Plan, Second Year	3.40%	2.26%	1.44%
Union pension plan participant [Member] | PacifiCorp [Member] | Pension Plan [Member] | Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest Crediting Rates for Cash Balance Plan, Third Year	3.15%	2.78%	2.35%
Interest Crediting Rates for Cash Balance Plan, Fourth Year		2.60%	3.05%
Interest Crediting Rates for Cash Balance Plan, Second Year	3.15%	2.78%	2.35%