Equity - Schedule of Effect of the Reclassification of Significant Items out of Accumulated Other Comprehensive Income on the Respective Line Items in the Consolidated Statements of Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Reclassification of significant items out of Accumulated Other Comprehensive Income
Total net realized losses	$ (135)	$ (103)
Amount Reclassified from AOCI
Reclassification of significant items out of Accumulated Other Comprehensive Income
Total reclassifications for the period	(138)	(270)
Unrealized Appreciation (Depreciation) of Fixed Maturity Securities on Which Allowance for Credit Losses Was Taken | Amount Reclassified from AOCI
Reclassification of significant items out of Accumulated Other Comprehensive Income
Total net realized losses	0	0
Total reclassifications for the period	0	0
Unrealized Appreciation (Depreciation) of All Other Investments | Amount Reclassified from AOCI
Reclassification of significant items out of Accumulated Other Comprehensive Income
Total net realized losses	(130)	(262)
Total reclassifications for the period	(130)	(262)
Retirement Plan Liabilities Adjustment | Amount Reclassified from AOCI
Reclassification of significant items out of Accumulated Other Comprehensive Income
Total reclassifications for the period	(8)	(8)
Prior-service credit | Amount Reclassified from AOCI
Reclassification of significant items out of Accumulated Other Comprehensive Income
Total reclassifications for the period	(1)	(1)
Actuarial losses | Amount Reclassified from AOCI
Reclassification of significant items out of Accumulated Other Comprehensive Income
Total reclassifications for the period	$ (7)	$ (7)