Variable Interest Entities (Schedule of Aggregate Assets, Liabilities, and Our Exposure to Loss from those VIEs) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Variable Interest Entity [Line Items]
Assets	$ 37,298,239	$ 37,196,124
Total liabilities	31,955,252	31,867,653
Variable Interest Entity Not Primary Beneficiary [Member] | Debt and equity [member]
Variable Interest Entity [Line Items]
Assets	795,645	791,111
Total liabilities	283,907	297,555
Gain (Loss) on Price Risk Derivatives, Net	24,914	14,776
Variable Interest Entity Not Primary Beneficiary [Member] | Miscellaneous Investments [Member]
Variable Interest Entity [Line Items]
Assets	395,338	388,408
Total liabilities	281,112	296,375
Gain (Loss) on Price Risk Derivatives, Net	24,914	14,776
Variable Interest Entity Not Primary Beneficiary [Member] | Partnership Interest [Member]
Variable Interest Entity [Line Items]
Assets	400,307	402,703
Total liabilities	2,795	1,180
Gain (Loss) on Price Risk Derivatives, Net	$ 0	$ 0