Investments - Investments - Unrealized Losses on AFS Securities (Details) $ in Millions	Sep. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions	5,242
Percentage of Gross Unrealized Losses Depressed Less than Twenty Percent of Cost or Amortized Cost	88.00%
ABS
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 1,798	$ 396
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	66	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	92	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	11	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	1,890	396
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	77	3
Collateralized Loan Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2,167	1,434
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	81	2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	683	147
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	29	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	2,850	1,581
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	110	2
CMBS
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2,887	594
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	284	7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	266	82
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	54	8
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	3,153	676
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	338	15
Corporate
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	12,682	3,698
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,531	65
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,533	234
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	381	9
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	14,215	3,932
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	1,912	74
Foreign Govt./Govt. Agencies
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	402	340
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	51	5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	172	16
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	20	1
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	574	356
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	71	6
Municipal
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	4,706	301
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	651	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	161	12
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	46	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	4,867	313
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	697	3
RMBS
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	3,023	1,869
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	375	23
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	612	94
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	121	4
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	3,635	1,963
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	496	27
U.S. Treasuries
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,764	2,301
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	185	13
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	423	23
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	60	1
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	2,187	2,324
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	245	14
Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	29,429	10,933
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	3,224	121
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	3,942	608
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	722	23
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	33,371	11,541
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	$ 3,946	$ 144

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

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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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Amount of accumulated unrealized loss on 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 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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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 less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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