Investments (Continuous Gross Unrealized Losses for Fixed Maturity Securities Available-For-Sale) (Details) $ in Millions	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	$ 50,711	$ 27,727
Less than 12 months Gross Unrealized Loss	$ 1,449	$ 1,031
Total number of securities in an unrealized loss position less than 12 months	3,545	2,177
Equal to or Greater than 12 Months Estimated Fair Value	$ 9,349	$ 6,236
Equal to or Greater than 12 Months Gross Unrealized Loss	$ 789	$ 401
Total number of securities in an unrealized loss position equal or greater than 12 months	793	690
U.S. corporate
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	$ 6,055	$ 4,338
Less than 12 months Gross Unrealized Loss	167	196
Equal to or Greater than 12 Months Estimated Fair Value	1,390	506
Equal to or Greater than 12 Months Gross Unrealized Loss	99	50
Foreign government
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	8,654	6,795
Less than 12 months Gross Unrealized Loss	399	305
Equal to or Greater than 12 Months Estimated Fair Value	3,501	836
Equal to or Greater than 12 Months Gross Unrealized Loss	364	100
Foreign corporate
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	9,318	4,856
Less than 12 months Gross Unrealized Loss	448	321
Equal to or Greater than 12 Months Estimated Fair Value	1,885	1,255
Equal to or Greater than 12 Months Gross Unrealized Loss	198	147
U.S. government and agency
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	15,354	4,619
Less than 12 months Gross Unrealized Loss	297	87
Equal to or Greater than 12 Months Estimated Fair Value	504	33
Equal to or Greater than 12 Months Gross Unrealized Loss	71	2
RMBS
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	6,466	1,531
Less than 12 months Gross Unrealized Loss	99	27
Equal to or Greater than 12 Months Estimated Fair Value	521	152
Equal to or Greater than 12 Months Gross Unrealized Loss	19	14
ABS
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	2,897	3,428
Less than 12 months Gross Unrealized Loss	13	26
Equal to or Greater than 12 Months Estimated Fair Value	840	2,842
Equal to or Greater than 12 Months Gross Unrealized Loss	14	49
Municipals
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	667	273
Less than 12 months Gross Unrealized Loss	12	6
Equal to or Greater than 12 Months Estimated Fair Value	49	0
Equal to or Greater than 12 Months Gross Unrealized Loss	3	0
CMBS
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	1,300	1,887
Less than 12 months Gross Unrealized Loss	14	63
Equal to or Greater than 12 Months Estimated Fair Value	659	612
Equal to or Greater than 12 Months Gross Unrealized Loss	21	39
Investment Grade
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	47,639	24,572
Less than 12 months Gross Unrealized Loss	1,329	829
Equal to or Greater than 12 Months Estimated Fair Value	8,046	5,841
Equal to or Greater than 12 Months Gross Unrealized Loss	$ 665	350
Total number of securities in an unrealized loss position equal or greater than 12 months	628
Below Investment Grade
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	$ 3,072	3,155
Less than 12 months Gross Unrealized Loss	120	202
Equal to or Greater than 12 Months Estimated Fair Value	1,303	395
Equal to or Greater than 12 Months Gross Unrealized Loss	$ 124	$ 51
Total number of securities in an unrealized loss position equal or greater than 12 months	165

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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