Fair Value Hierarchy - Summary of Changes in Fair Value for Level 3 Investments (Detail) - Investments - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 18,128	$ 16,109	$ 16,942	$ 13,902
Net realized gains/(losses)	113	103	344	428
Net unrealized gains/(losses)	(346)	(407)	(904)	(1,828)
Purchases	213	445	755	1,385
Sales	(111)	(236)	(621)	(741)
Settlements	(456)	(272)	(1,127)	(1,461)
Transfers into level 3	942	1,687	3,257	6,425
Transfers out of level 3	(1,154)	(475)	(1,317)	(1,156)
Ending balance	17,329	16,954	17,329	16,954
Corporate debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	7,520	6,576	7,003	4,527
Net realized gains/(losses)	88	69	301	224
Net unrealized gains/(losses)	(66)	(111)	(54)	(297)
Purchases	58	137	373	624
Sales	(53)	(78)	(185)	(151)
Settlements	(274)	(143)	(735)	(810)
Transfers into level 3	415	659	1,049	2,944
Transfers out of level 3	(738)	(371)	(802)	(323)
Ending balance	6,950	6,738	6,950	6,738
Securities backed by real estate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	878	1,067	827	1,078
Net realized gains/(losses)	1	7	10	21
Net unrealized gains/(losses)	(95)	(88)	(191)	(287)
Purchases	7	17	56	76
Sales	0	(47)	(58)	(96)
Settlements	(19)	(23)	(38)	(140)
Transfers into level 3	0	1	171	269
Transfers out of level 3	0	(22)	(5)	(9)
Ending balance	772	912	772	912
Other debt obligations
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	246	303	256	382
Net realized gains/(losses)	1	3	3	9
Net unrealized gains/(losses)	3	(3)	2	(8)
Purchases	6	4	1	28
Settlements	(7)	(23)	(13)	(127)
Ending balance	249	284	249	284
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	9,484	8,163	8,856	7,915
Net realized gains/(losses)	23	24	30	174
Net unrealized gains/(losses)	(188)	(205)	(661)	(1,236)
Purchases	142	287	325	657
Sales	(58)	(111)	(378)	(494)
Settlements	(156)	(83)	(341)	(384)
Transfers into level 3	527	1,027	2,037	3,212
Transfers out of level 3	(416)	(82)	(510)	(824)
Ending balance	$ 9,358	$ 9,020	$ 9,358	$ 9,020