Fair Value of Financial Instruments (Changes in Unrealized Gains (Losses) Included in OCI) (Details) - Fixed Maturity AFS Securities [Member] - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	$ (133)	$ (335)
Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	(122)	(325)
Foreign Government Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	(8)	(2)
ABS [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	(8)	(3)
Hybrid And Redeemable Preferred Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	2	$ (5)
Mortgage Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	$ 3