Investments - Schedule of Unrealized Net Capital Gains and Losses Included in AOCI (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Fair value
Fixed income securities, at fair value	$ 57,186	$ 52,747
Short-term investments	8,743	4,537
Derivative instruments	0	0
Gross Unrealized Gains
Fixed income securities	848	361
Short-term investments	0	0
Derivative instruments	0	0
Gross Unrealized Losses
Fixed income securities	(394)	(1,230)
Short-term investments	0	(2)
Derivative instruments	(2)	(2)
Unrealized net gains (losses)
Fixed income securities	454	(869)
Short-term investments	0	(2)
Derivative instruments	(2)	(2)
Investments classified as held for sale		(110)
Unrealized net capital gains and losses, pre-tax	452	(983)
Amounts recognized for:
Reclassification of noncontrolling interest	0	3
Deferred income taxes	(101)	209
Unrealized net capital gains and losses, after-tax	$ 351	$ (771)