Significant Accounting Policies - Deferred Acquisition Costs (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred acquisition costs, beginning of the period	$ 1,502	$ 1,219
Capitalizations	271	274
Amortization expense	(146)	(128)
Deferred acquisition costs, end of the period	$ 1,627	$ 1,365