Summary of Significant Accounting Policies - Adoption on Consolidated Condensed Statements of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income	$ 1,545	$ 891	$ 1,685
Provision for deferred income taxes	127	(50)	209
Changes in: Insurance reserves	$ 1,667	2,058	2,485
As Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income		1,103	1,703
Provision for deferred income taxes		5	213
Changes in: Insurance reserves		1,791	2,463
Effect of Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income		(212)	(18)
Provision for deferred income taxes		(55)	(4)
Changes in: Insurance reserves		$ 267	$ 22