Amount, after reinsurance, of paid claims and allocated claim adjustment expense used in claims development for short-duration insurance contracts. Excludes unallocated claim adjustment expense.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 4B
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=99384497&loc=SL65671311-158438

Name:	us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Medical Claims and Benefits Payable - Cumulative Paid Claims and Allocated Claims Adjustment Expenses (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2015
Product Information [Line Items]
Claims paid	$ 45,462
Benefit Year 2016
Product Information [Line Items]
Claims paid	15,039	$ 14,952	$ 13,403
Benefit Year 2017
Product Information [Line Items]
Claims paid	16,752	$ 15,130
Benefit Year 2018
Product Information [Line Items]
Claims paid	$ 13,671