Variable Interest Entities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Assets	$ 34,915,599	$ 32,590,690
Liabilities	31,477,274	29,356,065
Commitments approved	0	4,657	$ 0
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Commitments approved	10,100		$ 17,200
Other Assets [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Assets	43,400	37,200
Accounts Payable and Accrued Liabilities [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Liabilities	11,100	10,200
Other Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Assets	61,500	34,300
Unfunded Loan Commitment [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable interest entities, total exposure of other investments including unfunded commitments	$ 95,900	$ 72,700