Fair Value of Financial Instruments (Changes in Unrealized Gains (Losses) Included in OCI) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	$ (321)
Fixed Maturity AFS Securities [Member] | Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	(311)
Fixed Maturity AFS Securities [Member] | 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	(2)
Fixed Maturity AFS Securities [Member] | ABS [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	(3)
Fixed Maturity AFS Securities [Member] | 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	$ (5)