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, 2023 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ (10,065)	[1]
Ending Balance	(739,599)
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]
Beginning Balance	4,371
Net investment gains (losses) on investments arising during the period	(5,723)
Reclassification adjustment for (gains) losses included in net income	(269)
Reclassification due to allowance for credit losses recorded during the period	2,363
Impact of net unrealized investment (gains) losses	0
Ending Balance	742
Net Unrealized Investment Gains (Losses) on All Other Investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(2,161,026)
Net investment gains (losses) on investments arising during the period	(618,777)
Reclassification adjustment for (gains) losses included in net income	(17,477)
Reclassification due to allowance for credit losses recorded during the period	(2,363)
Impact of net unrealized investment (gains) losses	0
Ending Balance	(2,799,643)
Deferred Policy Acquisition Costs and Other Costs
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(1,198,422)
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	(432,798)
Ending Balance	(1,631,220)
Future Policy Benefits and Policyholders’ Account Balances and other liabilities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	1,488,679
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	575,026
Ending Balance	2,063,705
Income Tax Benefit (Expense)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	391,923
Net investment gains (losses) on investments arising during the period	131,182
Reclassification adjustment for (gains) losses included in net income	3,731
Reclassification due to allowance for credit losses recorded during the period	0
Impact of net unrealized investment (gains) losses	(29,876)
Ending Balance	496,960
Accumulated Other Comprehensive Income (Loss) Related To Net Unrealized Investment Gains (Losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(1,474,475)
Net investment gains (losses) on investments arising during the period	(493,318)
Reclassification adjustment for (gains) losses included in net income	(14,015)
Reclassification due to allowance for credit losses recorded during the period	0
Impact of net unrealized investment (gains) losses	112,352
Ending Balance	$ (1,869,456)

[1] Prior period amounts adjusted for the implementation of Accounting Standard Update ("ASU") 2018-12: Targeted Improvements to the Accounting for Long-Duration Contracts.