Future Contract Benefit (Summary of Discounted and Undiscounted Expected Future Gross premiums and Expected Future Benefit Payments) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Payout Annuities [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Expected future benefit payments, undiscounted	$ 3,552	$ 3,471
Expected future benefit payments, Discounted	1,943	2,003
Traditional Life [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Expected future gross premiums, undiscounted	13,410	13,166
Expected future benefit payments, undiscounted	13,372	13,026
Expected future gross premiums, discounted	8,802	8,887
Expected future benefit payments, Discounted	8,989	9,086
Group Protection [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Expected future benefit payments, undiscounted	7,148	7,063
Expected future benefit payments, Discounted	$ 6,093	$ 6,059