Investments - Unrealized Losses on AFS Securities (Details) $ in Millions	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions	1,500
Percentage of Gross Unrealized Losses Depressed Less than Twenty Percent of Cost or Amortized Cost	99.00%
ABS
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 396	$ 44
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(3)	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position	396	44
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(3)	0
CLOs
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,434	758
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(2)	(2)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	147	715
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	(5)
Debt Securities, Available-for-sale, Unrealized Loss Position	1,581	1,473
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(2)	(7)
CMBS
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	594	410
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(7)	(17)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	82	19
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(8)	(4)
Debt Securities, Available-for-sale, Unrealized Loss Position	676	429
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(15)	(21)
Corporate
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	3,698	466
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(65)	(13)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	234	212
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(9)	(18)
Debt Securities, Available-for-sale, Unrealized Loss Position	3,932	678
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(74)	(31)
Foreign government/government agencies
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	340	24
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(5)	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	16	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1)	0
Debt Securities, Available-for-sale, Unrealized Loss Position	356	24
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(6)	0
Municipal
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	301	34
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(3)	(1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	12	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position	313	34
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(3)	(1)
Residential mortgage-backed securities ("RMBS")
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,869	461
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(23)	(3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	94	21
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(4)	0
Debt Securities, Available-for-sale, Unrealized Loss Position	1,963	482
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(27)	(3)
U.S. Treasuries
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2,301	39
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(13)	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	23	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1)	0
Debt Securities, Available-for-sale, Unrealized Loss Position	2,324	39
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(14)	0
Securities available-for-sale and other
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	10,933	2,236
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(121)	(36)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	608	967
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(23)	(27)
Debt Securities, Available-for-sale, Unrealized Loss Position	11,541	3,203
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (144)	$ (63)

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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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 less than 12 months, 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 unrealized loss position without allowance for credit loss.

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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 unrealized loss position, 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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