Investments (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Gain (Loss) on Securities [Line Items]
Non-income producing fixed maturity securities	$ 0	$ 1,000,000
Non-Income Producing Mortgage Loans	7,000,000	7,000,000
Investments that exceed ten percent of stockholders' equity	0	0
Investment and derivative, realized gain (loss), coinsurance agreement	18,000,000
Gross gains	120,000,000	186,000,000	$ 220,000,000
Debt securities, available-for-sale, realized loss	261,000,000	90,000,000	220,000,000
Realized investment gains (losses)			20,000,000
Mortgage loan losses due to changes in expected credit losses	8,000,000	(10,000,000)	$ 21,000,000
Limited partnership investments	1,926,000,000	1,859,000,000
Undistributed earnings of limited partnership investments	$ 176,000,000	$ 266,000,000
Percentage of limited partnerships reported on a current basis	26.00%
Percentage of limited partnerships reported on a one month lag	5.00%
Limited partnerships invested in private debt and equity	76.00%	68.00%
Percentage of limited partnerships employing hedge fund strategies focused on fixed income and equity investments	24.00%	32.00%
Carrying value of ten largest limited partnerships	$ 633,000,000	$ 665,000,000
Carrying value of limited partnerships as percentage of aggregate partnership equity	1.00%	1.00%
Income as percentage of change in partnership equity for all limited partnerships	2.00%	2.00%	2.00%
Obligation to return cash	$ 1,000,000	$ 0
Derivative liability, subject to master netting arrangement, collateral, right to reclaim cash offset	0	0
Notional value		270,000,000
Other liabilities	(1,000,000)	(12,000,000)
Increase (decrease) fixed maturity securities	224,000,000
Increase (decrease) short term investments	4,000,000
Increase (decrease) accrued investment income	2,000,000
Increase (decrease) funds withheld liability	216,000,000
Embedded derivative, fair value of embedded derivative liability	14,000,000
Commitments to purchase or fund privately placed debt securities	1,455,000,000
Commitments to sell various privately placed debt securities	60,000,000
Carrying value of securities deposited under requirements of regulatory authorities	2,800,000,000	3,000,000,000
Cash and securities deposited as collateral for letters of credit	900,000,000	1,200,000,000
5.875% face amount of $500, due August 15, 2020 | Senior Notes
Gain (Loss) on Securities [Line Items]
Face amount			$ 400,000,000
Fixed maturity securities
Gain (Loss) on Securities [Line Items]
OCI, debt securities, available-for-sale, gain (loss), after adjustment, before tax	(7,850,000,000)	(1,272,000,000)	$ 1,637,000,000
Debt securities, available-for-sale, accrued interest, after allowance for credit loss	394,000,000	$ 369,000,000
Mortgage loans
Gain (Loss) on Securities [Line Items]
Financing receivable, accrued interest, after allowance for credit loss	4,000,000
Funds Withheld Liability Securities
Gain (Loss) on Securities [Line Items]
Gross gains	62,000,000
Debt securities, available-for-sale, realized loss	$ 44,000,000