Subsidiary Debt - AltaLink (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
ALP Investments [Member]
Debt Instrument [Line Items]
Par value	[1]	157
Other long-term debt		157	308
ALP Investments [Member] | Series 13-1 Senior Bonds, 3.265%, due 2020 [Member]
Debt Instrument [Line Items]
Par value		0
Other long-term debt		0	154
ALP Investments [Member] | Series 15-1 Senior Bonds, 2.244%, due 2022 [Member]
Debt Instrument [Line Items]
Par value	[1]	157
Other long-term debt		$ 157	154
ALP Investments [Member] | Subsidiary Debt [Member] | Series 13-1 Senior Bonds, 3.265%, due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.265%
ALP Investments [Member] | Subsidiary Debt [Member] | Series 15-1 Senior Bonds, 2.244%, due 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		2.244%
AltaLink, L.P. [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value	[1]	$ 3,733
Other long-term debt		$ 3,713	3,564
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2013-2 Notes, 3.621%, due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.621%
Par value		$ 0
Other long-term debt		$ 0	96
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2012-2 Notes, 2.978%, due 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		2.978%
Par value	[1]	$ 216
Other long-term debt		$ 216	212
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2013-4 Notes, 3.668%, due 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.668%
Par value	[1]	$ 393
Other long-term debt		$ 392	384
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2014-1 Notes, 3.399%, due 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.399%
Par value	[1]	$ 275
Other long-term debt		$ 275	269
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2016-1 Notes, 2.747%, due 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		2.747%
Par value	[1]	$ 275
Other long-term debt		$ 274	269
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2006-1 Notes, 5.249%, due 2036 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.249%
Par value	[1]	$ 118
Other long-term debt		$ 118	115
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2010-1 Notes, 5.381%, due 2040 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.381%
Par value	[1]	$ 98
Other long-term debt		$ 98	96
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2010-2 Notes, 4.872%, due 2040 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.872%
Par value	[1]	$ 118
Other long-term debt		$ 117	115
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2011-1 Notes, 4.462%, due 2041 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.462%
Par value	[1]	$ 216
Other long-term debt		$ 215	211
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2012-1 Notes, 3.99%, due 2042 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.99%
Par value	[1]	$ 413
Other long-term debt		$ 407	398
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2013-3 Notes, 4.922%, due 2043 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.922%
Par value	[1]	$ 275
Other long-term debt		$ 274	268
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2014-3 Notes, 4.054%, due 2044 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.054%
Par value	[1]	$ 232
Other long-term debt		$ 230	226
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2015-1 Notes, 4.090%, due 2045 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.09%
Par value	[1]	$ 275
Other long-term debt		$ 273	268
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2016-2 Notes, 3.717%, due 2046 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.717%
Par value	[1]	$ 354
Other long-term debt		$ 351	345
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2013-1 Notes, 4.446%, due 2053 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.446%
Par value	[1]	$ 196
Other long-term debt		$ 196	192
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2014-2 Notes, 4.274%, due 2064 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.274%
Par value	[1]	$ 102
Other long-term debt		$ 102	100
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Construction Loan, 5.620%, due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.62%
Par value	[1]	$ 7
Other long-term debt		$ 7	7
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2020-1 Notes, 1.509%, due 2030
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		1.509%
Par value		$ 177
Other long-term debt		175	0
BHE Transmission [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value	[1]	3,897
Other long-term debt		$ 3,877	$ 3,879

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