XML 44 R97.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Unpaid losses and loss adjustment expenses - Average historical claims duration (Detail) - Insurance Group [Member]
Dec. 31, 2019
GEICO [Member] | Physical Damage [Member]  
Shortduration Insurance Contracts Historical Claims Duration [Line Items]  
Average annual percentage payout of incurred losses, net of reinsurance, year one 98.00%
Average annual percentage payout of incurred losses, net of reinsurance, year two 2.00%
GEICO [Member] | Auto Liability [Member]  
Shortduration Insurance Contracts Historical Claims Duration [Line Items]  
Average annual percentage payout of incurred losses, net of reinsurance, year one 42.00%
Average annual percentage payout of incurred losses, net of reinsurance, year two 29.00%
Average annual percentage payout of incurred losses, net of reinsurance, year three 13.00%
Average annual percentage payout of incurred losses, net of reinsurance, year four 8.00%
Average annual percentage payout of incurred losses, net of reinsurance, year five 4.00%
Berkshire Hathaway Primary Group [Member] | Medical Professional Liability [Member]  
Shortduration Insurance Contracts Historical Claims Duration [Line Items]  
Average annual percentage payout of incurred losses, net of reinsurance, year one 2.00%
Average annual percentage payout of incurred losses, net of reinsurance, year two 7.00%
Average annual percentage payout of incurred losses, net of reinsurance, year three 12.00%
Average annual percentage payout of incurred losses, net of reinsurance, year four 15.00%
Average annual percentage payout of incurred losses, net of reinsurance, year five 15.00%
Average annual percentage payout of incurred losses, net of reinsurance, year six 12.00%
Average annual percentage payout of incurred losses, net of reinsurance, year seven 9.00%
Average annual percentage payout of incurred losses, net of reinsurance, year eight 6.00%
Average annual percentage payout of incurred losses, net of reinsurance, year nine 5.00%
Average annual percentage payout of incurred losses, net of reinsurance, year ten 4.00%
Berkshire Hathaway Primary Group [Member] | Workers' Compensation and Other Casualty [Member]  
Shortduration Insurance Contracts Historical Claims Duration [Line Items]  
Average annual percentage payout of incurred losses, net of reinsurance, year one 16.00%
Average annual percentage payout of incurred losses, net of reinsurance, year two 21.00%
Average annual percentage payout of incurred losses, net of reinsurance, year three 16.00%
Average annual percentage payout of incurred losses, net of reinsurance, year four 12.00%
Average annual percentage payout of incurred losses, net of reinsurance, year five 8.00%
Average annual percentage payout of incurred losses, net of reinsurance, year six 5.00%
Average annual percentage payout of incurred losses, net of reinsurance, year seven 3.00%
Average annual percentage payout of incurred losses, net of reinsurance, year eight 2.00%
Average annual percentage payout of incurred losses, net of reinsurance, year nine 1.00%
Average annual percentage payout of incurred losses, net of reinsurance, year ten 2.00%
Berkshire Hathaway Reinsurance Group [Member] | Property [Member]  
Shortduration Insurance Contracts Historical Claims Duration [Line Items]  
Average annual percentage payout of incurred losses, net of reinsurance, year one 19.00%
Average annual percentage payout of incurred losses, net of reinsurance, year two 36.00%
Average annual percentage payout of incurred losses, net of reinsurance, year three 17.00%
Average annual percentage payout of incurred losses, net of reinsurance, year four 9.00%
Average annual percentage payout of incurred losses, net of reinsurance, year five 4.00%
Average annual percentage payout of incurred losses, net of reinsurance, year six 3.00%
Average annual percentage payout of incurred losses, net of reinsurance, year seven 1.00%
Average annual percentage payout of incurred losses, net of reinsurance, year eight 1.00%
Average annual percentage payout of incurred losses, net of reinsurance, year nine 0.00%
Average annual percentage payout of incurred losses, net of reinsurance, year ten 1.00%
Berkshire Hathaway Reinsurance Group [Member] | Casualty [Member]  
Shortduration Insurance Contracts Historical Claims Duration [Line Items]  
Average annual percentage payout of incurred losses, net of reinsurance, year one 10.00%
Average annual percentage payout of incurred losses, net of reinsurance, year two 17.00%
Average annual percentage payout of incurred losses, net of reinsurance, year three 13.00%
Average annual percentage payout of incurred losses, net of reinsurance, year four 8.00%
Average annual percentage payout of incurred losses, net of reinsurance, year five 7.00%
Average annual percentage payout of incurred losses, net of reinsurance, year six 5.00%
Average annual percentage payout of incurred losses, net of reinsurance, year seven 4.00%
Average annual percentage payout of incurred losses, net of reinsurance, year eight 2.00%
Average annual percentage payout of incurred losses, net of reinsurance, year nine 2.00%
Average annual percentage payout of incurred losses, net of reinsurance, year ten 1.00%