Medical Claims and Related Payables - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Jun. 30, 2024	Dec. 31, 2023
Insurance [Abstract]
Related payables associated with retained liability	$ 13.5	$ 14.7
Reduction in medical services expense	$ 54.3

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