Subsidiary Debt - Northern Powergrid (Details) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Par value		$ 49,759
Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value		36,108
Other long-term debt		36,319	$ 30,672
PacifiCorp [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value		8,667
Other long-term debt		$ 8,612	$ 7,658
PacifiCorp [Member] | Subsidiary Debt [Member] | Minimum [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate		0.14%	1.60%
PacifiCorp [Member] | Subsidiary Debt [Member] | Maximum [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate		0.16%	1.80%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value	[1]	$ 3,285
Other long-term debt		3,259	$ 3,221
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | Bonds, 8.875%, due 2020 [Member]
Debt Instrument [Line Items]
Par value		0
Other long-term debt		$ 0	135
Debt Instrument, Interest Rate, Stated Percentage		8.875%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | Bonds, 9.25%, due 2020 [Member]
Debt Instrument [Line Items]
Par value		$ 0
Other long-term debt		$ 0	265
Debt Instrument, Interest Rate, Stated Percentage		9.25%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | European Investment Bank loans, 4.133% to 4.586%, due 2019 to 2022 [Member]
Debt Instrument [Line Items]
Par value	[1]	$ 206
Other long-term debt		$ 206	252
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | European Investment Bank loans, 4.133% to 4.586%, due 2019 to 2022 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.133%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | Bonds, 7.25%, due 2022 [Member]
Debt Instrument [Line Items]
Par value	[1]	$ 274
Other long-term debt		$ 277	270
Debt Instrument, Interest Rate, Stated Percentage		7.25%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | Bonds, 2.50%, due 2025 [Member]
Debt Instrument [Line Items]
Par value	[1]	$ 205
Other long-term debt		$ 203	197
Debt Instrument, Interest Rate, Stated Percentage		2.50%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | European Investment Bank loan, 2.073%, due 2025 [Member]
Debt Instrument [Line Items]
Par value	[1]	$ 68
Other long-term debt		$ 70	68
Debt Instrument, Interest Rate, Stated Percentage		2.073%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | European Investment Bank loans, 2.564%, due 2017 [Member]
Debt Instrument [Line Items]
Par value	[1]	$ 342
Other long-term debt		$ 340	330
Debt Instrument, Interest Rate, Stated Percentage		2.564%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | Bonds, 7.25%, due 2028 [Member]
Debt Instrument [Line Items]
Par value	[1]	$ 254
Other long-term debt		$ 257	250
Debt Instrument, Interest Rate, Stated Percentage		7.25%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | Bonds, 5.125%, due 2035 [Member]
Debt Instrument [Line Items]
Par value	[1]	$ 274
Other long-term debt		$ 270	262
Debt Instrument, Interest Rate, Stated Percentage		5.125%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | Bonds, 5.125%, due 2035 [Member]
Debt Instrument [Line Items]
Par value	[1]	$ 205
Other long-term debt		$ 203	197
Debt Instrument, Interest Rate, Stated Percentage		5.125%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | Bonds, 4.375%, due 2032 [Member]
Debt Instrument [Line Items]
Par value	[1]	$ 205
Other long-term debt		$ 202	196
Debt Instrument, Interest Rate, Stated Percentage		4.375%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | Variable-rate bond, due 2026 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate		2.03%
Par value	[1],[2]	$ 186
Other long-term debt	[2]	$ 183	214
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate		3.07%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | Variable-rate bond, due 2026, 100% variable
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate		2.02%
Par value		$ 41
Other long-term debt		41	0
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | Guaranteed Bonds, 2.75%, due May 2049 [Member]
Debt Instrument [Line Items]
Par value	[1]	205
Other long-term debt		$ 202	196
Debt Instrument, Interest Rate, Stated Percentage		2.75%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | Bonds, 2.25%, due 2059 [Member]
Debt Instrument [Line Items]
Par value	[1]	$ 410
Other long-term debt		$ 402	389
Debt Instrument, Interest Rate, Stated Percentage		2.25%
Northern Powergrid Holdings [Member] | Subsidiary Debt [Member] | Bonds, 1.875%, due 2062
Debt Instrument [Line Items]
Par value		$ 410
Other long-term debt		$ 403	$ 0
Debt Instrument, Interest Rate, Stated Percentage		1.875%

[1] The par values for these debt instruments are denominated in sterling.

[2] Amortizes semiannually and the Company has entered into an interest rate swap that fixes the interest rate on 89% of the outstanding debt. The variable interest rate as of December 31, 2020 was 2.03% (including 2.0% margin) and the fixed interest rate was 3.07% (including 2.0% margin), resulting in a blended rate of 2.96%.(3)Amortizes semiannually and is 100% variable based on LIBOR. The variable interest rate as of December 31, 2020 was 2.02% (including 2.0% margin).