Equity (Net Unrealized Investment Gains (Losses) in AOCI on AFS Fixed Maturity Securities with Allowance for Credit Losses and All Other Investments) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2025 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Begining Balance	$ 4,701,980
Ending Balance	6,187,825
Net Unrealized Investment Gains (Losses) on Available-for-Sale Fixed Maturity Securities on which an allowance for credit losses has been recognized
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Begining Balance	893
Net investment gains (losses) on investments arising during the period	421
Reclassification adjustment for (gains) losses included in net income	(3,239)
Reclassification due to allowance for credit losses recorded during the period	363
Impact of net unrealized investment (gains) losses	0
Ending Balance	(1,562)
Net Unrealized Investment Gains (Losses) on All Other Investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Begining Balance	(1,847,178)
Net investment gains (losses) on investments arising during the period	1,083,148
Reclassification adjustment for (gains) losses included in net income	81,750
Reclassification due to allowance for credit losses recorded during the period	(363)
Impact of net unrealized investment (gains) losses	0
Ending Balance	(682,643)
Other Costs
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Begining Balance	(583,709)
Net investment gains (losses) on investments arising during the period	0
Reclassification adjustment for (gains) losses included in net income	0
Reclassification due to allowance for credit losses recorded during the period	0
Impact of net unrealized investment (gains) losses	275,496
Ending Balance	(308,213)
Future Policy Benefits and Policyholders’ Account Balances and other liabilities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Begining Balance	920,455
Net investment gains (losses) on investments arising during the period	0
Reclassification adjustment for (gains) losses included in net income	0
Reclassification due to allowance for credit losses recorded during the period	0
Impact of net unrealized investment (gains) losses	(422,367)
Ending Balance	498,088
Income Tax Benefit (Expense)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Begining Balance	316,837
Net investment gains (losses) on investments arising during the period	(227,402)
Reclassification adjustment for (gains) losses included in net income	(16,477)
Reclassification due to allowance for credit losses recorded during the period	0
Impact of net unrealized investment (gains) losses	30,845
Ending Balance	103,803
Accumulated Other Comprehensive Income (Loss) Related To Net Unrealized Investment Gains (Losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Begining Balance	(1,192,702)
Net investment gains (losses) on investments arising during the period	856,167
Reclassification adjustment for (gains) losses included in net income	62,034
Reclassification due to allowance for credit losses recorded during the period	0
Impact of net unrealized investment (gains) losses	(116,026)
Ending Balance	$ (390,527)