Significant Accounting Policies - Deferred Acquisition Costs (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred acquisition costs, beginning of the period	$ 1,219	$ 879
Capitalizations	274	279
Amortization expense	(128)	(103)
Deferred acquisition costs, end of the period	$ 1,365	$ 1,055