Investments (Components of Net Investment Gains Losses) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Other net investment gains (losses):
Mortgage loans	$ (2)	$ (80)	$ 58	$ (143)
Real estate and real estate joint ventures	368	2	416	3
Other limited partnership interests	(8)	1	(13)	5
Other (2), (3)	22	101	42	125
Subtotal - investment portfolio gains (losses)	441	242	575	(71)
Change In Estimated Fair Value Of Other Limited Partnership Interests And Real Estate Joint Ventures	5	(13)	14	(12)
Non-investment portfolio gains (losses) (4)	1,159	2	1,150	26
Subtotal	1,164	(11)	1,164	14
Total net investment gains (losses)	1,605	231	1,739	(57)
Changes In Estimated Fair Value Subsequent To Purchase For Equity Securities	50	63	113	(193)
Gain (Loss) on Termination of Lease		81		81
Fixed Maturity Securities
Marketable Securities, Gain (Loss) [Abstract]
Net investment gains (losses)	5	150	(62)	154
Equity Securities
Marketable Securities, Gain (Loss) [Abstract]
Net investment gains (losses)	55	72	130	(212)
Cash Flow Hedging [Member]
Other net investment gains (losses):
Total net investment gains (losses)	19	79	40	87
Currency Swap [Member] \| Cash Flow Hedging [Member]
Other net investment gains (losses):
Total net investment gains (losses)	95	287	(124)	(164)
FVO Securities (1)
Marketable Securities, Gain (Loss) [Abstract]
Net investment gains (losses)	1	(4)	4	(3)
Foreign Currency Gain (Loss) [Member] \| Reclassification out of Accumulated Other Comprehensive Income \| Currency Swap [Member] \| Cash Flow Hedging [Member]
Other net investment gains (losses):
Total net investment gains (losses)	$ 19	$ 43	$ 48	$ 55

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