Schedule VI (SUPPLEMENTARY INFORMATION CONCERNING PROPERTY AND CASUALTY OPERATIONS) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Abstract]
Deferred Policy Acquisition Costs		$ 4,462	$ 4,260	$ 4,244
Net Reserves for Unpaid Losses		59,195	56,759	53,164
Unearned Premiums		20,360	19,101	17,652
Net Premiums Earned		38,905	35,035	31,800
Net Investment Income		3,381	3,133	3,074
Current Year Claim and Claim Adjustment Expense		24,495	22,966	22,124
Prior Year Claim and Claim Adjustment Expense		(1,153)	(986)	(414)
Net Losses and Loss Expenses Incurred Related to Prior Year	[1]	(1,153)	(986)	(414)
Amortization of Deferred Policy Acquisition Costs		6,873	6,440	6,076
Net Paid Losses and Loss Expenses		20,323	17,884	17,434
Net Premiums Written		$ 40,170	$ 36,474	$ 32,471

[1] Relates to prior period loss reserve development only and excludes prior period development related to reinstatement premiums, expense adjustments, and earned premiums totaling $277 million, $60 million, and $19 million for 2022, 2021, and 2020, respectively.