Medical Claims Liability - Schedule of Change in Medical Claims Liability (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance, January 1	$ 14,243	$ 12,438	$ 7,473
Less: reinsurance recoverable	23	23	20
Balance, January 1, net	14,220	12,415	7,453
Acquisitions and divestitures	105	0	3,856
Incurred related to:
Current year	112,896	100,385	86,765
Prior years	(1,367)	(1,783)	(501)
Total incurred	111,529	98,602	86,264
Paid related to:
Current year	97,799	87,427	78,838
Prior years	11,336	9,370	6,320
Total paid	109,135	96,797	85,158
Balance, December 31, net	16,719	14,220	12,415
Plus: reinsurance recoverable	26	23	23
Balance, December 31	$ 16,745	$ 14,243	$ 12,438

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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Amount of increase (decrease) in the cost of settling unpaid claims after deduction of reinsurance recoveries related to the acquisition of a business. Includes, but is not limited to, claims which have been incurred but not reported.

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Amount, after effects of reinsurance, of payments to settle claims incurred in the current period and related claims settlement costs.

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Amount, after effects of reinsurance, of payments to settle claims incurred in prior periods and related claims settlement costs.

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Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred and costs incurred in the claim settlement process.

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Liability as of the balance sheet date for amounts representing estimated cost of settling unpaid claims under the terms of the underlying insurance policies, less estimated reinsurance recoveries on such claims. This includes an estimate for claims which have been incurred but not reported. Claim adjustment expenses represent the costs estimated to be incurred in the settlement of unpaid claims.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount, after valuation allowance, recoverable under reinsurance contracts for losses reported to the ceding insurer but not yet paid and amounts expected for incurred losses and settlement expenses, which have not yet been reported to the ceding insurer.

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Amount, after effects of reinsurance, of expense for claims incurred in the current reporting period and related claims settlement costs.

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Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred in prior reporting periods and related claims settlement costs.

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