Medical Claims and Related Payables - Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Insurance [Abstract]
Related payables associated with retained liability	$ 13.2	$ 7.0

Liability For Claims And Claims Adjustment Expense, Amounts Recoverable under risk sharing arrangements

No definition available.

Name:	agl_LiabilityForClaimsAndClaimsAdjustmentExpenseAmountsRecoverable
Namespace Prefix:	agl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant