Investments (Components of Net Investment Gains Losses) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings		$ (129)	$ (40)
Net credit loss (provision) release	$ (154)
Fixed maturity securities AFS - Net gain (losses) on sales and disposals	451	396	45
Equity securities - Net gains (losses) on sales and disposals	16	50	118
Change In Estimated Fair Value Of Equity Securities	(153)	84	(193)
Other net investment gains (losses):
Mortgage loans	(213)	(11)	(56)
Real estate and real estate joint ventures	7	399	326
Other limited partnership interests	(15)	6	9
Other (3)	198	(142)	(169)
Subtotal - investment portfolio gains (losses)	137	653	40
Change In Estimated Fair Value Of Other Limited Partnership Interests And Real Estate Joint Ventures	(4)	(14)	12
Non-investment portfolio gains (losses)	(243)	(195)	(350)
Subtotal	(247)	(209)	(338)
Net investment gains (losses)	(110)	444	(298)
Changes In Estimated Fair Value Subsequent To Purchase For Equity Securities	(127)	122	(81)
Gain (Loss) on Termination of Lease	87
Fixed Maturity Securities
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings		(129)	(40)
Net credit loss (provision) release	(154)
Net investment gains (losses)	297	267	5
Equity securities
Marketable Securities, Gain (Loss) [Abstract]
Net investment gains (losses)	(137)	134	(75)
Finance Corporate Debt Securities
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings		(1)	(9)
Foreign government
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings		(81)	(9)
Consumer Domestic Corporate Debt Securities
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings		(23)	(20)
Industrial Domestic Corporate Debt Securities
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings		(22)	(2)
RMBS
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings		(2)
Lease Agreements
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings		(30)	(105)
Tax credit partnerships
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(9)	(92)
Other limited partnership interests
Other net investment gains (losses):
Other (3)		46	(83)
Cash Flow Hedging [Member]
Other net investment gains (losses):
Net investment gains (losses)	207	8	0
Currency Swap [Member] \| Cash Flow Hedging [Member]
Other net investment gains (losses):
Net investment gains (losses)	851	$ 240	$ 0
Foreign Currency Gain (Loss) [Member] \| Reclassification out of Accumulated Other Comprehensive Income \| Currency Swap [Member] \| Cash Flow Hedging [Member]
Other net investment gains (losses):
Net investment gains (losses)	$ 129

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