Medical Claims and Benefits Payable - Incurred Claims and Allocated Adjustment Expense (Details) claim in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) claim	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Product Information [Line Items]
Incurred Claims and Allocated Claims Adjustment Expenses	$ 27,175	$ 23,704	$ 15,820
Incurred Claims and Allocated Claims Adjustment Expenses	67,438
Total IBNP	2,588
Benefit Year 2020
Product Information [Line Items]
Incurred Claims and Allocated Claims Adjustment Expenses	16,000	16,056	$ 16,233
Total IBNP	$ 27
Cumulative number of reported claims (in claim) | claim	138
Benefit Year 2021
Product Information [Line Items]
Incurred Claims and Allocated Claims Adjustment Expenses	$ 23,979	$ 24,167
Total IBNP	$ 108
Cumulative number of reported claims (in claim) | claim	236
Benefit Year 2022
Product Information [Line Items]
Incurred Claims and Allocated Claims Adjustment Expenses	$ 27,459
Total IBNP	$ 2,453
Cumulative number of reported claims (in claim) | claim	264