Variable Interest Entities (Schedule of Aggregate Assets, Liabilities, and Our Exposure to Loss from those VIEs) (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Variable Interest Entity [Line Items]
Assets	$ 39,859,653	$ 39,895,540
Total liabilities	34,262,668	34,208,770
Variable Interest Entity Not Primary Beneficiary [Member] | Debt and equity [member]
Variable Interest Entity [Line Items]
Assets	780,703	732,072
Total liabilities	197,991	193,397
Maximum Exposure to Loss	45,506	40,130
Variable Interest Entity Not Primary Beneficiary [Member] | Miscellaneous Investments [Member]
Variable Interest Entity [Line Items]
Assets	427,121	400,188
Total liabilities	196,952	191,170
Maximum Exposure to Loss	45,506	40,130
Variable Interest Entity Not Primary Beneficiary [Member] | Partnership Interest [Member]
Variable Interest Entity [Line Items]
Assets	353,582	331,884
Total liabilities	1,039	2,227
Maximum Exposure to Loss	$ 0	$ 0