Unaudited Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Investments:
Debt securities available for sale, at fair value	$ 36,453	$ 35,051
Equity securities, at fair value	2,280	1,864
Other investments, at fair value	3,381	3,136
Investments accounted for using the equity method	6,852	6,453
Total investments	48,966	46,504
Cash	1,109	993
Accrued investment income	325	338
Investment in operating affiliates	1,323	1,313
Premiums receivable (net of allowance for credit losses: $41 and $43)	7,160	5,723
Reinsurance recoverable on unpaid and paid losses and loss adjustment expenses (net of allowance for credit losses: $18 and $17)	9,964	9,526
Contractholder receivables (net of allowance for credit losses: $7 and $7)	2,264	2,270
Ceded unearned premiums	3,669	2,659
Deferred acquisition costs	1,794	1,717
Receivable for securities sold	564	180
Goodwill and intangible assets	1,163	1,222
Other assets	6,878	6,796
Total assets	85,179	79,241
Liabilities
Reserve for losses and loss adjustment expenses	34,775	33,547
Unearned premiums	11,493	10,100
Reinsurance balances payable	3,234	2,320
Contractholder payables	2,270	2,277
Collateral held for insured obligations	240	237
Senior notes	4,286	2,729
Payable for securities purchased	1,136	308
Other liabilities	3,715	3,517
Total liabilities	61,149	55,035
Commitments and contingencies (refer to Note 11)
Shareholders' Equity
Non-cumulative preferred shares	830	830
Common shares ($0.0011 par, shares issued: 602.7 and 599.8)	1	1
Additional paid-in capital	2,873	2,735
Retained earnings	29,129	27,045
Accumulated other comprehensive income (loss), net of deferred income tax	(413)	5
Common shares held in treasury, at cost (shares: 261.8 and 240.8)	(8,390)	(6,410)
Total shareholders' equity available to Arch	24,030	24,206
Total liabilities and shareholders' equity	85,179	79,241
Fixed maturities available for sale, at fair value (amortized cost: $33,427 and $32,329; net of allowance for credit losses: $16 and $20)
Investments:
Debt securities available for sale, at fair value	33,155	32,426
Short-term investments available for sale, at fair value (amortized cost: $3,298 and $2,624; net of allowance for credit losses: $0 and $0)
Investments:
Debt securities available for sale, at fair value	$ 3,298	$ 2,625

Cash received by the Company as collateral related to contractholder payables.

No definition available.

Name:	acgl_CollateralHeldForInsuredObligations
Namespace Prefix:	acgl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Certain insurance policies written by the Company’s insurance operations feature large deductibles, primarily in its construction and national accounts lines of business. Under such contracts, the Company is obligated to pay the claimant for the full amount of the claim. The Company is subsequently reimbursed by the policyholder for the deductible amount. These amounts are included on a gross basis in the consolidated balance sheet in contractholder payables and contractholder receivables, respectively. In the event that the Company is unable to collect from the policyholder, the Company would be liable for such defaulted amounts. Collateral, primarily in the form of letters of credit, cash and trusts, is obtained from the policyholder to mitigate the Company’s credit risk. In the instances where the Company receives collateral in the form of cash, the Company reflects it in “Collateral held for insured obligations.”

+ References

No definition available.