Medical Claims Liability - Schedule of Change in Medical Claims Liability (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance, January 1	$ 16,745	$ 14,243
Less: Reinsurance recoverable	26	23
Balance, January 1, net	16,719	14,220
Acquisitions and divestitures		249
Incurred related to:
Current year	60,335	56,179
Prior years	(1,554)	(1,029)
Total incurred	58,781	55,150
Paid related to:
Current year	46,970	42,886
Prior years	11,666	10,161
Total paid	58,636	53,047
Balance, June 30, net	16,864	16,572
Plus: Reinsurance recoverable	20	9
Balance, June 30	16,884	16,581
Medicaid
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance, January 1	11,253	9,845
Less: Reinsurance recoverable	7	23
Balance, January 1, net	11,246	9,822
Acquisitions and divestitures		0
Incurred related to:
Current year	40,622	37,803
Prior years	(1,153)	(770)
Total incurred	39,469	37,033
Paid related to:
Current year	31,837	29,007
Prior years	7,890	6,808
Total paid	39,727	35,815
Balance, June 30, net	10,988	11,040
Plus: Reinsurance recoverable	5	9
Balance, June 30	10,993	11,049
Medicare
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance, January 1	3,431	2,286
Less: Reinsurance recoverable	0	0
Balance, January 1, net	3,431	2,286
Acquisitions and divestitures		0
Incurred related to:
Current year	10,083	9,918
Prior years	(191)	(46)
Total incurred	9,892	9,872
Paid related to:
Current year	7,726	6,977
Prior years	2,357	1,784
Total paid	10,083	8,761
Balance, June 30, net	3,240	3,397
Plus: Reinsurance recoverable	0	0
Balance, June 30	3,240	3,397
Commercial
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance, January 1	1,921	2,014
Less: Reinsurance recoverable	19	0
Balance, January 1, net	1,902	2,014
Acquisitions and divestitures		0
Incurred related to:
Current year	8,857	7,001
Prior years	(208)	(198)
Total incurred	8,649	6,803
Paid related to:
Current year	6,751	5,475
Prior years	1,282	1,489
Total paid	8,033	6,964
Balance, June 30, net	2,518	1,853
Plus: Reinsurance recoverable	15	0
Balance, June 30	2,533	1,853
Other
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance, January 1	140	98
Less: Reinsurance recoverable	0	0
Balance, January 1, net	140	98
Acquisitions and divestitures		249
Incurred related to:
Current year	773	1,457
Prior years	(2)	(15)
Total incurred	771	1,442
Paid related to:
Current year	656	1,427
Prior years	137	80
Total paid	793	1,507
Balance, June 30, net	118	282
Plus: Reinsurance recoverable	0	0
Balance, June 30	$ 118	$ 282