Investments - Schedule of Available-for-Sale Securities Whose Value is Below Amortized Cost (Details) $ in Millions	Dec. 31, 2025 USD ($) security	Dec. 31, 2024 USD ($) security
Fair Value
Nine months or greater, but less than twelve months	$ 22,143	$ 30,166
Twelve months or greater	37,525	36,345
Total	59,668	66,511
Gross Unrealized Losses
Nine months or greater, but less than twelve months	3,658	4,537
Twelve months or greater	5,341	6,468
Total	$ 8,999	$ 11,005
Number of Securities
Total | security	6,089,000,000	6,985,000,000
Fair Value Decline, Greater Than 20%
Fair Value
Less than six months	$ 2,355	$ 5,405
Six months or greater, but less than nine months	351	371
Nine months or greater, but less than twelve months	302	71
Twelve months or greater	5,214	4,440
Total	8,222	10,287
Gross Unrealized Losses
Less than six months	839	1,621
Six months or greater, but less than nine months	163	198
Nine months or greater, but less than twelve months	119	28
Twelve months or greater	2,195	2,218
Total	$ 3,316	$ 4,065
Number of Securities
Less than six months | security	445	799
Six months or greater, but less than nine months | security	65	216
Nine months or greater, but less than twelve months | security	99	37
Twelve months or greater | security	902	741
Total | security	1,511	1,793