Regulatory Matters - PacifiCorp - Regulatory Assets (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Regulatory Assets [Line Items]
Regulatory assets		$ 189	$ 150
Regulatory assets, noncurrent		2,761	4,307
Total regulatory assets		2,950	4,457
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided		1,100	2,800
Deferred Income Tax Charge [Member]
Regulatory Assets [Line Items]
Total regulatory assets	[1]	$ 143	1,754
Regulatory asset amortization period years	[1]	Various
Employee benefit plans [Member]
Regulatory Assets [Line Items]
Total regulatory assets	[2]	$ 675	816
Regulatory asset amortization period years	[2]	15.7540740740741
Unamortized contract values [Member]
Regulatory Assets [Line Items]
Total regulatory assets		$ 89	98
Regulatory asset amortization period years		6
Deferred net power costs [Member]
Regulatory Assets [Line Items]
Total regulatory assets		$ 58	38
Regulatory asset amortization period years		2.27586206896552
Unrealized loss on regulated derivative contracts [Member]
Regulatory Assets [Line Items]
Total regulatory assets		$ 122	154
Regulatory asset amortization period years		4
Asset Retirement Obligation Costs [Member]
Regulatory Assets [Line Items]
Total regulatory assets		$ 334	301
Regulatory asset amortization period years		13.1467065868263
PacifiCorp [Member]
Regulatory Assets [Line Items]
Regulatory assets		$ 31	53
Regulatory assets, noncurrent		1,030	1,490
Total regulatory assets		1,061	1,543
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided		589	1,019
PacifiCorp [Member] | Deferred Income Tax Charge [Member]
Regulatory Assets [Line Items]
Total regulatory assets	[3]	$ 0	421
Regulatory asset amortization period years	[3]	N/A
PacifiCorp [Member] | Employee benefit plans [Member]
Regulatory Assets [Line Items]
Total regulatory assets	[4]	$ 418	525
Regulatory asset amortization period years	[4]	20 years
PacifiCorp [Member] | Utah mine disposition [Member]
Regulatory Assets [Line Items]
Total regulatory assets	[5]	$ 156	166
Regulatory asset amortization period years	[5]	Various
PacifiCorp [Member] | Unamortized contract values [Member]
Regulatory Assets [Line Items]
Total regulatory assets		$ 89	98
Regulatory asset amortization period years		6 years
PacifiCorp [Member] | Deferred net power costs [Member]
Regulatory Assets [Line Items]
Total regulatory assets		$ 21	33
Regulatory asset amortization period years		1 year
PacifiCorp [Member] | Unrealized loss on regulated derivative contracts [Member]
Regulatory Assets [Line Items]
Total regulatory assets		$ 101	73
Regulatory asset amortization period years		4 years
PacifiCorp [Member] | Asset Retirement Obligation Costs [Member]
Regulatory Assets [Line Items]
Total regulatory assets		$ 100	82
Regulatory asset amortization period years		22 years
PacifiCorp [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets [Line Items]
Total regulatory assets		$ 176	$ 145
Regulatory asset amortization period years		Various

[1] Amounts primarily represent income tax benefits related to certain property-related basis differences and other various differences that were previously passed on to customers and will be included in regulated rates when the temporary differences reverse.

[2] (1)Represents amounts not yet recognized as a component of net periodic benefit cost that are expected to be included in regulated rates when recognized.

[3] (1)Amount primarily represents income tax benefits and expense related to certain property-related basis differences and other various items that were previously passed on to customers and will be included in regulated rates when the temporary differences reverse.

[4] (2)Represents amounts not yet recognized as a component of net periodic benefit cost that are expected to be included in rates when recognized.

[5] (3)Amounts represent regulatory assets established as a result of the Utah mine disposition in 2015 for the net property, plant and equipment not considered probable of disallowance and for the portion of losses associated with the assets held for sale, UMWA 1974 Pension Plan withdrawal and closure costs incurred to date considered probable of recove