Investments - Schedule of Unrealized Net Capital Gains and Losses Included in AOCI (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Fair value
Fixed income securities, at fair value	$ 50,777	$ 48,865
Short-term investments	4,318	5,144
Derivative instruments	0	0
Gross Unrealized Gains
Fixed income securities	408	650
Short-term investments	0	0
Derivative instruments	0	0
Gross Unrealized Losses
Fixed income securities	(1,468)	(1,434)
Short-term investments	(2)	(1)
Derivative instruments	(2)	(2)
Unrealized net gains (losses)
Fixed income securities	(1,060)	(784)
Short-term investments	(2)	(1)
Derivative instruments	(2)	(2)
Limited partnership interests	0	(4)
Unrealized net capital gains and losses, pre-tax	(1,064)	(791)
Amounts recognized for:
Reclassification of noncontrolling interest	12	13
Deferred income taxes	233	174
Unrealized net capital gains and losses, after-tax	$ (819)	$ (604)