Investments - Investments - Unrealized Losses on AFS Securities (Details) $ in Millions	Jun. 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	4,747
Percentage of Gross Unrealized Losses Depressed Less than Twenty Percent of Cost or Amortized Cost	95.00%
ABS
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 40	$ 3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,117	396
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	26	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	1,143	396
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	41	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, Accumulated Loss	88	2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2,351	1,434
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	23	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	527	147
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	2,878	1,581
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	111	2
CMBS
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	198	7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	3,026	594
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	16	8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	95	82
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	3,121	676
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	214	15
Corporate
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,196	65
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	13,163	3,698
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	123	9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	650	234
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	13,813	3,932
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	1,319	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, Accumulated Loss	42	5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	515	340
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	10	1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	93	16
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	608	356
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	52	6
Municipal
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	385	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	4,553	301
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	4	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	23	12
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	4,576	313
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	389	3
RMBS
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	267	23
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	3,366	1,869
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	39	4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	295	94
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	3,661	1,963
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	306	27
U.S. Treasuries
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	136	13
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2,299	2,301
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	4	1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	38	23
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	2,337	2,324
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	140	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, Accumulated Loss	2,352	121
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	30,390	10,933
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	220	23
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,747	608
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	32,137	11,541
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	$ 2,572	$ 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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