Significant business acquisitions - Narrative (Detail) - USD ($) $ in Millions			12 Months Ended
	Oct. 19, 2022	Nov. 01, 2020	Dec. 31, 2022		Dec. 31, 2021		Dec. 31, 2020
Business Acquisition [Line Items]
Revenues			$ 207,771		$ 191,252		$ 166,733
Net earnings			(22,819)		89,795		42,521
Goodwill			78,119	[1]	$ 73,875	[1]	$ 73,734
Alleghany Corporation [Member]
Business Acquisition [Line Items]
Business acquisition, date completed	Oct. 19, 2022
Business acquisition, cash consideration	$ 11,500
Business acquisition, agreement date	Mar. 20, 2022
Revenues			2,400
Net earnings			$ 216
Assets acquired	$ 35,590
Liabilities assumed	$ 24,085
Berkshire Hathaway Energy [Member] | Dominion Energy, Inc. [Member]
Business Acquisition [Line Items]
Business acquisition, date completed		Nov. 01, 2020
Business acquisition, cash consideration		$ 2,500
Berkshire Hathaway Energy [Member] | Dominion Energy, Inc. [Member] | Cove Point [Member]
Business Acquisition [Line Items]
Variable interest entity, ownership percentage		25.00%
Berkshire Hathaway Energy [Member] | Dominion Energy, Inc. [Member] | General Partner [Member] | Cove Point [Member]
Business Acquisition [Line Items]
Variable interest entity, ownership percentage		100.00%
Berkshire Hathaway Energy [Member] | Dominion Energy, Inc. [Member] | Limited Partner [Member] | Cove Point [Member]
Business Acquisition [Line Items]
Variable interest entity, ownership percentage		25.00%

[1] Net of accumulated goodwill impairments of $11.0 billion as of December 31, 2022 and 2021