Insurance - Analysis of changes in the liability for losses and loss adjustment expenses, net of reinsurance (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Analysis of changes in the liability for losses and loss adjustment expenses, net of reinsurance
Balance at beginning of year	$ 11,074	$ 10,392
Less reinsurance recoverables, net of allowance	3,419	3,117
Net liability at beginning of year	7,655	7,275
Provision for losses and LAE occurring in the current period	2,869	2,543
Net decrease in the provision for claims of prior years	(226)	(208)
Total losses and LAE incurred	2,643	2,335
Payments for losses and LAE of:
Current year	(667)	(589)
Prior years	(1,501)	(1,430)
Total payments	(2,168)	(2,019)
Foreign currency translation and other	1	0
Net liability at end of period	8,131	7,591
Add back reinsurance recoverables, net of allowance	3,936	3,400
Gross unpaid losses and LAE included in the balance sheet at end of period	$ 12,067	$ 10,991