Investments - Investments - Unrealized Losses on AFS Securities (Details) $ in Millions	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Debt Securities, Available-for-sale [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	787
Percentage of Gross Unrealized Losses Depressed Less than Twenty Percent of Cost or Amortized Cost	96.00%
ABS
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months FV	$ 137	$ 44
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
12 Months or More FV	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Total FV	137	44
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	0	0
Collateralized Loan Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months FV	703	758
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1	2
12 Months or More FV	251	715
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	5
Total FV	954	1,473
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	1	7
CMBS
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months FV	130	410
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1	17
12 Months or More FV	91	19
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	7	4
Total FV	221	429
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	8	21
Corporate
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months FV	1,436	466
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	23	13
12 Months or More FV	207	212
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	9	18
Total FV	1,643	678
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	32	31
Foreign Govt./Govt. Agencies
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months FV	153	24
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	3	0
12 Months or More FV	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Total FV	153	24
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	3	0
Municipal
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months FV	263	34
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2	1
12 Months or More FV	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Total FV	263	34
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	2	1
RMBS
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months FV	725	461
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	8	3
12 Months or More FV	6	21
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Total FV	731	482
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	8	3
U.S. Treasuries
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months FV	377	39
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	3	0
12 Months or More FV	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Total FV	377	39
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	3	0
Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months FV	3,924	2,236
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	41	36
12 Months or More FV	555	967
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	16	27
Total FV	4,479	3,203
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 57	$ 63

Percentage of gross unrealized losses depressed less than twenty percent of cost or amortized cost.

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

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- Definition

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
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This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months.

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- Definition

Number of investment positions in available-for-sale investments in a continuous unrealized loss position for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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