Investments (Continuous Gross Unrealized Losses for Fixed Maturity Securities Available-For-Sale) (Details) $ in Millions	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	$ 40,484	$ 27,727
Less than 12 months Gross Unrealized Loss	$ 1,309	$ 1,031
Total number of securities in an unrealized loss position less than 12 months	2,939	2,177
Equal to or Greater than 12 Months Estimated Fair Value	$ 8,453	$ 6,236
Equal to or Greater than 12 Months Gross Unrealized Loss	$ 671	$ 401
Total number of securities in an unrealized loss position equal or greater than 12 months	827	690
U.S. corporate
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	$ 5,081	$ 4,338
Less than 12 months Gross Unrealized Loss	169	196
Equal to or Greater than 12 Months Estimated Fair Value	1,278	506
Equal to or Greater than 12 Months Gross Unrealized Loss	77	50
Foreign government
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	8,679	6,795
Less than 12 months Gross Unrealized Loss	409	305
Equal to or Greater than 12 Months Estimated Fair Value	2,751	836
Equal to or Greater than 12 Months Gross Unrealized Loss	338	100
Foreign corporate
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	5,915	4,856
Less than 12 months Gross Unrealized Loss	275	321
Equal to or Greater than 12 Months Estimated Fair Value	1,991	1,255
Equal to or Greater than 12 Months Gross Unrealized Loss	178	147
U.S. government and agency
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	10,982	4,619
Less than 12 months Gross Unrealized Loss	318	87
Equal to or Greater than 12 Months Estimated Fair Value	144	33
Equal to or Greater than 12 Months Gross Unrealized Loss	17	2
RMBS
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	5,353	1,531
Less than 12 months Gross Unrealized Loss	98	27
Equal to or Greater than 12 Months Estimated Fair Value	442	152
Equal to or Greater than 12 Months Gross Unrealized Loss	18	14
ABS
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	3,105	3,428
Less than 12 months Gross Unrealized Loss	13	26
Equal to or Greater than 12 Months Estimated Fair Value	1,078	2,842
Equal to or Greater than 12 Months Gross Unrealized Loss	16	49
Municipals
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	554	273
Less than 12 months Gross Unrealized Loss	13	6
Equal to or Greater than 12 Months Estimated Fair Value	6	0
Equal to or Greater than 12 Months Gross Unrealized Loss	0	0
CMBS
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	815	1,887
Less than 12 months Gross Unrealized Loss	14	63
Equal to or Greater than 12 Months Estimated Fair Value	763	612
Equal to or Greater than 12 Months Gross Unrealized Loss	27	39
Investment Grade
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	38,324	24,572
Less than 12 months Gross Unrealized Loss	1,225	829
Equal to or Greater than 12 Months Estimated Fair Value	7,132	5,841
Equal to or Greater than 12 Months Gross Unrealized Loss	548	350
Below Investment Grade
Debt Securities, Available-for-sale [Line Items]
Less than 12 months Estimated Fair Value	2,160	3,155
Less than 12 months Gross Unrealized Loss	84	202
Equal to or Greater than 12 Months Estimated Fair Value	1,321	395
Equal to or Greater than 12 Months Gross Unrealized Loss	$ 123	$ 51

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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