Reserve for Property and Casualty Insurance Claims and Claims Expense - Schedule of Reconciliation of the Net Incurred and Paid Claims Development to Reserve for Property and Casualty Insurance Claims and Claims Expense (Details) - USD ($)
$ in Millions

Dec. 31, 2025

Dec. 31, 2024

Dec. 31, 2023

Dec. 31, 2022

Reserve for Property and Casualty Insurance Claims and Claims Expense - Schedule of Reconciliation of the Net Incurred and Paid Claims Development to Reserve for Property and Casualty Insurance Claims and Claims Expense (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Claims Development [Line Items]
Reserve for property and casualty insurance claims and claims expense	$ 41,079	$ 41,917
Property and casualty
Claims Development [Line Items]
Net outstanding liabilities	33,067
ULAE	1,551
Recoverables	8,012	8,602	$ 8,396	$ 9,176
ULAE	134
Reserve for property and casualty insurance claims and claims expense	41,079	$ 41,917	$ 39,858	$ 37,541
Auto insurance - liability coverage
Claims Development [Line Items]
Net outstanding liabilities	21,521
Auto insurance - liability coverage \| Property and casualty
Claims Development [Line Items]
Net outstanding liabilities	21,521
Recoverables	6,301
Auto insurance - physical damage coverage
Claims Development [Line Items]
Net outstanding liabilities	597
Auto insurance - physical damage coverage \| Property and casualty
Claims Development [Line Items]
Net outstanding liabilities	597
Recoverables	18
Homeowners insurance
Claims Development [Line Items]
Net outstanding liabilities	4,122
Homeowners insurance \| Property and casualty
Claims Development [Line Items]
Net outstanding liabilities	4,122
Recoverables	679
Other personal lines \| Property and casualty
Claims Development [Line Items]
Net outstanding liabilities	2,664
Recoverables	204
Commercial lines \| Property and casualty
Claims Development [Line Items]
Net outstanding liabilities	1,133
Recoverables	231
Other business lines \| Property and casualty
Claims Development [Line Items]
Net outstanding liabilities	93
Recoverables	14
Protection Services \| Property and casualty
Claims Development [Line Items]
Net outstanding liabilities	60
Recoverables	12
Run-off Property-Liability
Claims Development [Line Items]
Reserve for property and casualty insurance claims and claims expense	761
Run-off Property-Liability \| Property and casualty
Claims Development [Line Items]
Net outstanding liabilities	1,326
Recoverables	419
Other \| Property and casualty
Claims Development [Line Items]
Net outstanding liabilities	$ 0