Medical Claims and Related Payables - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Insurance [Abstract]
Related payables associated with retained liability	$ 12.0	$ 14.7

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