Reserve for Unpaid Losses and Loss Adjustment Expenses - P&C Liabilities for Unpaid Losses and Loss Adjustment Expense (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Beginning liabilities for unpaid losses and loss adjustment expenses, gross	$ 39,659
Less: payments
Ending liabilities for unpaid losses and loss adjustment expenses, gross	40,601
Property, Liability and Casualty Insurance Product Line
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Beginning liabilities for unpaid losses and loss adjustment expenses, gross	31,449	$ 29,622
Reinsurance and other recoverables	6,205	5,931	$ 6,081	$ 5,725
Beginning liabilities for unpaid losses and loss adjustment expenses, net	26,285	25,259	$ 25,368	$ 23,897
Provision for unpaid losses and loss adjustment expense
Current accident year	6,361	5,968
Prior accident year development [1]	(147)	170
Total provision for unpaid losses and loss adjustment expenses	6,214	6,138
Less: payments
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year	(1,571)	(1,549)
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years	(3,671)	(3,155)
Total payments	(5,242)	(4,704)
Foreign currency adjustment	(55)	1
Ending liabilities for unpaid losses and loss adjustment expenses, net	26,285	25,259
Ending liabilities for unpaid losses and loss adjustment expenses, gross	32,490	31,190
Property, Liability and Casualty Insurance Product Line | Reinsurance Contract [Axis]: Adverse Development Cover Navigators Group
Provision for unpaid losses and loss adjustment expense
Deferred Revenue	$ 0	$ 73