Subsidiary Debt Subsidiary Debt - AltaLink (Details) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Par value		$ 37,014
Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value		28,263
Other long-term debt		28,097	$ 28,641
ALP Investments [Member]
Debt Instrument [Line Items]
Par value	[1]	441
Other long-term debt		442	481
ALP Investments [Member] | Series 12-1 Senior Bonds, 3.674%, due 2019 [Member]
Debt Instrument [Line Items]
Par value	[1]	147
Other long-term debt		148	162
ALP Investments [Member] | Series 13-1 Senior Bonds, 3.265%, due 2020 [Member]
Debt Instrument [Line Items]
Par value	[1]	147
Other long-term debt		148	161
ALP Investments [Member] | Series 15-1 Senior Bonds, 2.244%, due 2022 [Member]
Debt Instrument [Line Items]
Par value	[1]	147
Other long-term debt		$ 146	$ 158
ALP Investments [Member] | Subsidiary Debt [Member] | Series 12-1 Senior Bonds, 3.674%, due 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.674%	3.674%
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%	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%	2.244%
AltaLink, L.P. [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value	[1]	$ 3,407
Other long-term debt		3,392	$ 3,840
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Series 2008-1 Notes, 5.243%, due 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			5.243%
Par value	[1]	0
Other long-term debt		$ 0	$ 159
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%	3.621%
Par value	[1]	$ 92
Other long-term debt		$ 92	$ 99
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%	2.978%
Par value	[1]	$ 202
Other long-term debt		$ 201	$ 218
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%	3.668%
Par value	[1]	$ 366
Other long-term debt		$ 366	$ 397
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%	3.399%
Par value	[1]	$ 256
Other long-term debt		$ 256	$ 278
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%	2.747%
Par value	[1]	$ 256
Other long-term debt		$ 255	$ 277
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%	5.249%
Par value	[1]	$ 110
Other long-term debt		$ 109	$ 119
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%	5.381%
Par value	[1]	$ 92
Other long-term debt		$ 91	$ 99
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%	4.872%
Par value	[1]	$ 110
Other long-term debt		$ 109	$ 119
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%	4.462%
Par value	[1]	$ 202
Other long-term debt		$ 201	$ 218
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%	3.99%
Par value	[1]	$ 385
Other long-term debt		$ 380	$ 412
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%	4.922%
Par value	[1]	$ 256
Other long-term debt		$ 256	$ 278
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%	4.054%
Par value	[1]	$ 216
Other long-term debt		$ 215	$ 233
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%	4.09%
Par value	[1]	$ 256
Other long-term debt		$ 255	$ 277
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%	3.717%
Par value	[1]	$ 330
Other long-term debt		$ 328	$ 356
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%	4.446%
Par value	[1]	$ 183
Other long-term debt		$ 183	$ 198
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%	4.274%
Par value	[1]	$ 95
Other long-term debt		$ 95	$ 103
AltaLink, L.P. [Member] | Subsidiary Debt [Member] | Construction Loan, 4.950%, due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.66%	5.66%
Par value	[1]	$ 8
Other long-term debt		8	$ 13
BHE Transmission [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value	[1]	3,856
Other long-term debt		$ 3,842	$ 4,334

[1] ns): Par Value(1) 2018 2017AltaLink Investments, L.P.: Series 12-1 Senior Bonds, 3.674%, due 2019$147 $148 $162Series 13-1 Senior Bonds, 3.265%, due 2020147 148 161Series 15-1 Senior Bonds, 2.244%, due 2022147 146 158Total AltaLink Investments, L.P.441 442 481 AltaLink, L.P.: Series 2008-1 Notes, 5.243%, due 2018— — 159Series 2013-2 Notes, 3.621%, due 202092 92 99Series 2012-2 Notes, 2.978%, due 2022202 201 218Series 2013-4 Notes, 3.668%, due 2023366 366 397Series 2014-1 Notes, 3.399%, due 2024256 256 278Series 2016-1 Notes, 2.747%, due 2026256 255 277Series 2006-1 Notes, 5.249%, due 2036110 109 119Series 2010-1 Notes, 5.381%, due 204092 91 99Series 2010-2 Notes, 4.872%, due 2040110 109 119Series 2011-1 Notes, 4.462%, due 2041202 201 218Series 2012-1 Notes, 3.990%, due 2042385 380 412Series 2013-3 Notes, 4.922%, due 2043256 256 278Series 2014-3 Notes, 4.054%, due 2044216 215 233Series 2015-1 Notes, 4.090%, due 2045256 255 277Series 2016-2 Notes, 3.717%, due 2046330 328 356Series 2013-1 Notes, 4.446%, due 2053183 183 198Series 2014-2 Notes, 4.274%, due 206495 95 103Total AltaLink, L.P.3,407 3,392 3,840 Other: Construction Loan, 5.660%, due 20208 8 13 Total BHE Transmission$3,856 $3,842 $4,334(1)The par values for these debt instruments are denominated in Canadian dollars.