10-Q Medical Claims Payable (Narrative) (Details) $ in Millions	Sep. 30, 2023 USD ($)
Short-Duration Insurance Contract, Accident Year 2021 [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 481
Short-Duration Insurance Contract, Accident Year 2022 [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1,421
Short-Duration Insurance Contract, Accident Year 2023 [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 14,011

Undiscounted amount, after reinsurance, of incurred-but-not-reported (IBNR) liabilities plus expected development on reported claims, for claims and allocated claim adjustment expense for short-duration insurance contracts. Excludes unallocated claim adjustment expense.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 4D
-Subparagraph (a)
-SubTopic 40
-Topic 944
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480081/944-40-50-4D

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 4E
-SubTopic 40
-Topic 944
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480081/944-40-50-4E

Name:	us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant