Statutory Information - Summary of statutory capital, surplus and net income (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Bermuda
Statutory Accounting Practices [Line Items]
Actual statutory capital and surplus	[1]	$ 19,546,128	$ 17,528,510
Required statutory capital and surplus	[1]	6,449,878	5,661,301
Statutory net income (loss)		1,729,925	2,370,746	$ 1,579,889
Ireland
Statutory Accounting Practices [Line Items]
Actual statutory capital and surplus	[1]	968,443	958,200
Required statutory capital and surplus	[1]	815,194	794,933
Statutory net income (loss)		(52,757)	25,191	18,397
United States
Statutory Accounting Practices [Line Items]
Actual statutory capital and surplus	[1]	6,194,954	5,600,652
Required statutory capital and surplus	[1]	1,748,543	1,717,646
Statutory net income (loss)		219,524	345,790	143,271
United Kingdom
Statutory Accounting Practices [Line Items]
Actual statutory capital and surplus	[1]	1,018,092	902,002
Required statutory capital and surplus	[1]	543,104	563,164
Statutory net income (loss)		56,818	35,286	4,078
Canada
Statutory Accounting Practices [Line Items]
Actual statutory capital and surplus	[1]	68,637	70,063
Required statutory capital and surplus	[1]	47,825	42,513
Statutory net income (loss)		9,215	6,985	(1,049)
Australia
Statutory Accounting Practices [Line Items]
Actual statutory capital and surplus	[1]	284,998	283,693
Required statutory capital and surplus	[1]	175,885	214,022
Statutory net income (loss)		$ 38,538	$ 11,874	$ (8,601)

[1] Such amounts include ownership interests in affiliated insurance and reinsurance subsidiaries.