Investment Information - Limited partnership interests (Details) - USD ($) $ in Thousands		Mar. 31, 2022	Dec. 31, 2021
Schedule of Equity Method Investments [Line Items]
Maximum Exposure to Loss		$ 3,472,261	$ 3,248,206
Aggregate unfunded commitments		3,100,000	3,000,000
Equity method investments
Schedule of Equity Method Investments [Line Items]
Maximum Exposure to Loss	[1]	3,325,543	3,077,611
Aggregate unfunded commitments		2,700,000	2,600,000
Fair value option
Schedule of Equity Method Investments [Line Items]
Maximum Exposure to Loss	[2]	146,718	170,595
Aggregate unfunded commitments		$ 21,300	$ 18,800

[1] Aggregate unfunded commitments were $2.7 billion at March 31, 2022, compared to $2.6 billion at December 31, 2021.

[2] Aggregate unfunded commitments were $21.3 million at March 31, 2022, compared to $18.8 million at December 31, 2021.