Significant Accounting Policies - Deferred Acquisition Costs (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred acquisition costs, beginning of the period	$ 1,502	$ 1,219
Capitalizations	134	135
Amortization expense	(76)	(64)
Deferred acquisition costs, end of the period	$ 1,560	$ 1,290