Significant Accounting Policies - Deferred Acquisition Costs (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred acquisition costs, beginning of the period	$ 1,219	$ 879
Capitalizations	135	139
Amortization expense	(64)	(47)
Deferred acquisition costs, end of the period	$ 1,290	$ 971