Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 13, 2020	Jun. 30, 2019
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Registrant Name	BERKSHIRE HATHAWAY INC
Entity Central Index Key	0001067983
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity File Number	001-14905
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-0813844
Entity Address, Address Line One	3555 Farnam Street
Entity Address, City or Town	Omaha
Entity Address, State or Province	NE
Entity Address, Postal Zip Code	68131
City Area Code	402
Local Phone Number	346-1400
Document Annual Report	true
Document Transition Report	false
Entity Public Float			$ 417,300,000,000
Documents Incorporated by Reference	Portions of the Proxy Statement for the Registrant’s Annual Meeting to be held May 2, 2020 are incorporated in Part III.
Common Class A [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		700,396
Security 12b Title	Class A Common Stock
Trading Symbol	BRK.A
Security Exchange Name	NYSE
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		1,385,994,959
Security 12b Title	Class B Common Stock
Trading Symbol	BRK.B
Security Exchange Name	NYSE
M 0.750 Senior Notes Due 2023 [Member]
Document Information [Line Items]
Security 12b Title	0.750% Senior Notes due 2023
Trading Symbol	BRK23
Security Exchange Name	NYSE
M 1.125 Senior Notes Due 2027 [Member]
Document Information [Line Items]
Security 12b Title	1.125% Senior Notes due 2027
Trading Symbol	BRK27
Security Exchange Name	NYSE
M 1.625 Senior Notes Due 2035 [Member]
Document Information [Line Items]
Security 12b Title	1.625% Senior Notes due 2035
Trading Symbol	BRK35
Security Exchange Name	NYSE
M 0.500 Senior Notes Due 2020 [Member]
Document Information [Line Items]
Security 12b Title	0.500% Senior Notes due 2020
Trading Symbol	BRK20
Security Exchange Name	NYSE
M 1.300 Senior Notes Due 2024 [Member]
Document Information [Line Items]
Security 12b Title	1.300% Senior Notes due 2024
Trading Symbol	BRK24
Security Exchange Name	NYSE
M 2.150 Senior Notes Due 2028 [Member]
Document Information [Line Items]
Security 12b Title	2.150% Senior Notes due 2028
Trading Symbol	BRK28
Security Exchange Name	NYSE
M 0.250 Senior Notes Due 2021 [Member]
Document Information [Line Items]
Security 12b Title	0.250% Senior Notes due 2021
Trading Symbol	BRK21
Security Exchange Name	NYSE
M 0.625 Senior Notes Due 2023 [Member]
Document Information [Line Items]
Security 12b Title	0.625% Senior Notes due 2023
Trading Symbol	BRK23A
Security Exchange Name	NYSE
M 2.375 Senior Notes Due 2039 [Member]
Document Information [Line Items]
Security 12b Title	2.375% Senior Notes due 2039
Trading Symbol	BRK39
Security Exchange Name	NYSE
M 2.625 Senior Notes Due 2059 [Member]
Document Information [Line Items]
Security 12b Title	2.625% Senior Notes due 2059
Trading Symbol	BRK59
Security Exchange Name	NYSE