Investments - Schedule of Unrealized Net Capital Gains and Losses Included in AOCI (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Fair value
Fixed income securities	$ 48,865	$ 42,485
Short-term investments	5,144	4,173
Derivative instruments	0	0
Gross unrealized Gains
Fixed income securities	650	92
Short-term investments	0	0
Derivative instruments	0	0
Gross unrealized Losses
Fixed income securities	(1,434)	(2,977)
Short-term investments	(1)	(1)
Derivative instruments	(2)	(3)
Unrealized net gains (losses)
Fixed income securities	(784)	(2,885)
Short-term investments	(1)	(1)
Derivative instruments	(2)	(3)
Limited partnership interests	(4)	2
Unrealized net capital gains and losses, pre-tax	(791)	(2,887)
Reclassification of noncontrolling interest	13	23
Deferred income taxes	174	609
Unrealized net capital gains and losses, after-tax	$ (604)	$ (2,255)