Medical Costs Payable Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Medical costs payable, beginning of period	$ 32,395	$ 29,056	$ 24,483
Acquisitions (dispositions), net	(755)	1	308
Reported medical costs:
Current year	264,885	242,734	211,252
Prior years	(700)	(840)	(410)
Total reported medical costs	264,185	241,894	210,842
Medical payments:
Payments for current year	(231,890)	(211,380)	(184,049)
Payments for prior years	(29,532)	(27,176)	(22,528)
Total medical payments	(261,422)	(238,556)	(206,577)
Medical costs payable included within businesses held for sale	(179)	0	0
Medical costs payable, end of period	$ 34,224	$ 32,395	$ 29,056

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The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date.

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