| Document and Entity Information | Aug. 03, 2019 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | BERKSHIRE HATHAWAY INC |
| Entity Incorporation State Country Code | DE |
| Amendment Flag | false |
| Entity Central Index Key | 0001067983 |
| Document Type | 8-K |
| Document Period End Date | Aug. 3, 2019 |
| Entity File Number | 001-14905 |
| 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 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Class A [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Class A Common Stock |
| Trading Symbol | BRK.A |
| Security Exchange Name | NYSE |
| Common Class B [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Class B Common Stock |
| Trading Symbol | BRK.B |
| Security Exchange Name | NYSE |
| M 0.750 Senior Notes Due 2023 [Member] | |
| Document And Entity 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 And Entity 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 And Entity 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 And Entity 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 And Entity 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 And Entity 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 And Entity 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 And Entity 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 And Entity 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 And Entity Information [Line Items] | |
| Security 12b Title | 2.625% Senior Notes due 2059 |
| Trading Symbol | BRK59 |
| Security Exchange Name | NYSE |
