Reinsurance - Reinsurance Recoverables (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Ceded Credit Risk [Line Items]
Reinsurance recoverables	$ 4,200
Allowance for uncollectible reinsurance	(35)
Market risk benefits	993		$ 1,450
Total reinsurance recoverables	5,158
Berkshire Hathway Life Insurance Company Of Nebraska and Other Recoverables
Ceded Credit Risk [Line Items]
Market risk benefits	993
Fair value of collateral contractually required to meet or exceed carrying value of recoverable
Ceded Credit Risk [Line Items]
Reinsurance recoverables	694
Collateral provisions exist that may mitigate risk of credit loss
Ceded Credit Risk [Line Items]
Reinsurance recoverables	3,093
No collateral
Ceded Credit Risk [Line Items]
Reinsurance recoverables	413
Variable Annuity | Berkshire Hathway Life Insurance Company Of Nebraska and Other Recoverables
Ceded Credit Risk [Line Items]
Market risk benefits		$ 1,400
Variable Annuity | Berkshire Hathway Life Insurance Company Of Nebraska and Other Recoverables | GMDB
Ceded Credit Risk [Line Items]
Market risk benefits		$ 711
Ongoing Operations
Ceded Credit Risk [Line Items]
Reinsurance recoverables	424
Ongoing Operations | Other Current Assets
Ceded Credit Risk [Line Items]
Reinsurance recoverables	238
Ongoing Operations | A- equivalent and higher current ratings
Ceded Credit Risk [Line Items]
Reinsurance recoverables	86
Ongoing Operations | BBB- to BBB+ equivalent current credit ratings
Ceded Credit Risk [Line Items]
Reinsurance recoverables	59
Ongoing Operations | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	279
Ongoing Operations | Fair value of collateral contractually required to meet or exceed carrying value of recoverable
Ceded Credit Risk [Line Items]
Reinsurance recoverables	157
Ongoing Operations | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | A- equivalent and higher current ratings
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Ongoing Operations | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | BBB- to BBB+ equivalent current credit ratings
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Ongoing Operations | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	157
Ongoing Operations | Collateral provisions exist that may mitigate risk of credit loss
Ceded Credit Risk [Line Items]
Reinsurance recoverables	3
Ongoing Operations | Collateral provisions exist that may mitigate risk of credit loss | A- equivalent and higher current ratings
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Ongoing Operations | Collateral provisions exist that may mitigate risk of credit loss | BBB- to BBB+ equivalent current credit ratings
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Ongoing Operations | Collateral provisions exist that may mitigate risk of credit loss | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	3
Ongoing Operations | No collateral
Ceded Credit Risk [Line Items]
Reinsurance recoverables	264
Ongoing Operations | No collateral | A- equivalent and higher current ratings
Ceded Credit Risk [Line Items]
Reinsurance recoverables	86
Ongoing Operations | No collateral | BBB- to BBB+ equivalent current credit ratings
Ceded Credit Risk [Line Items]
Reinsurance recoverables	59
Ongoing Operations | No collateral | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	119
Acquisition, disposition or run-off activities
Ceded Credit Risk [Line Items]
Reinsurance recoverables	3,776
Acquisition, disposition or run-off activities | BBB+ equivalent and higher current ratings | Lincoln National Life and Lincoln Life & Annuity of New York
Ceded Credit Risk [Line Items]
Reinsurance recoverables	2,690
Acquisition, disposition or run-off activities | BBB+ equivalent and higher current ratings | Empower Annuity Insurance Company
Ceded Credit Risk [Line Items]
Reinsurance recoverables	130
Acquisition, disposition or run-off activities | BBB+ equivalent and higher current ratings | Prudential Insurance Company of America
Ceded Credit Risk [Line Items]
Reinsurance recoverables	364
Acquisition, disposition or run-off activities | BBB+ equivalent and higher current ratings | Life Insurance Company of North America
Ceded Credit Risk [Line Items]
Reinsurance recoverables	372
Acquisition, disposition or run-off activities | BBB+ equivalent and higher current ratings | Other
Ceded Credit Risk [Line Items]
Reinsurance recoverables	209
Acquisition, disposition or run-off activities | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	11
Acquisition, disposition or run-off activities | Fair value of collateral contractually required to meet or exceed carrying value of recoverable
Ceded Credit Risk [Line Items]
Reinsurance recoverables	537
Acquisition, disposition or run-off activities | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | BBB+ equivalent and higher current ratings | Lincoln National Life and Lincoln Life & Annuity of New York
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or run-off activities | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | BBB+ equivalent and higher current ratings | Empower Annuity Insurance Company
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or run-off activities | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | BBB+ equivalent and higher current ratings | Prudential Insurance Company of America
Ceded Credit Risk [Line Items]
Reinsurance recoverables	364
Acquisition, disposition or run-off activities | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | BBB+ equivalent and higher current ratings | Life Insurance Company of North America
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or run-off activities | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | BBB+ equivalent and higher current ratings | Other
Ceded Credit Risk [Line Items]
Reinsurance recoverables	173
Acquisition, disposition or run-off activities | Fair value of collateral contractually required to meet or exceed carrying value of recoverable | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or run-off activities | Collateral provisions exist that may mitigate risk of credit loss
Ceded Credit Risk [Line Items]
Reinsurance recoverables	3,090
Acquisition, disposition or run-off activities | Collateral provisions exist that may mitigate risk of credit loss | BBB+ equivalent and higher current ratings | Lincoln National Life and Lincoln Life & Annuity of New York
Ceded Credit Risk [Line Items]
Reinsurance recoverables	2,690
Acquisition, disposition or run-off activities | Collateral provisions exist that may mitigate risk of credit loss | BBB+ equivalent and higher current ratings | Empower Annuity Insurance Company
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or run-off activities | Collateral provisions exist that may mitigate risk of credit loss | BBB+ equivalent and higher current ratings | Prudential Insurance Company of America
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or run-off activities | Collateral provisions exist that may mitigate risk of credit loss | BBB+ equivalent and higher current ratings | Life Insurance Company of North America
Ceded Credit Risk [Line Items]
Reinsurance recoverables	372
Acquisition, disposition or run-off activities | Collateral provisions exist that may mitigate risk of credit loss | BBB+ equivalent and higher current ratings | Other
Ceded Credit Risk [Line Items]
Reinsurance recoverables	21
Acquisition, disposition or run-off activities | Collateral provisions exist that may mitigate risk of credit loss | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	7
Acquisition, disposition or run-off activities | No collateral
Ceded Credit Risk [Line Items]
Reinsurance recoverables	149
Acquisition, disposition or run-off activities | No collateral | BBB+ equivalent and higher current ratings | Lincoln National Life and Lincoln Life & Annuity of New York
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or run-off activities | No collateral | BBB+ equivalent and higher current ratings | Empower Annuity Insurance Company
Ceded Credit Risk [Line Items]
Reinsurance recoverables	130
Acquisition, disposition or run-off activities | No collateral | BBB+ equivalent and higher current ratings | Prudential Insurance Company of America
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or run-off activities | No collateral | BBB+ equivalent and higher current ratings | Life Insurance Company of North America
Ceded Credit Risk [Line Items]
Reinsurance recoverables	0
Acquisition, disposition or run-off activities | No collateral | BBB+ equivalent and higher current ratings | Other
Ceded Credit Risk [Line Items]
Reinsurance recoverables	15
Acquisition, disposition or run-off activities | No collateral | Not rated
Ceded Credit Risk [Line Items]
Reinsurance recoverables	$ 4