Medical Claims and Related Payables - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Insurance [Abstract]
Related payables associated with retained liability	$ 29.3	$ 13.3

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