Investments - Schedule of AFS Securities (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Jan. 01, 2020
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	$ 89,044	$ 82,544
AFS securities allowance for credit losses	(111)	(104)	$ (78)	$ (17)
Gross Unrealized Gains	4,678	7,515
Gross Unrealized Losses	(1,182)	(582)
Available-for-sale securities	92,429	89,373
Investments, excluding investments in Related Party
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	82,190	76,100
AFS securities allowance for credit losses	(111)	(103)
Gross Unrealized Gains	4,579	7,395
Gross Unrealized Losses	(1,134)	(539)
Available-for-sale securities	85,524	82,853
U.S. government and agencies \| Investments, excluding investments in Related Party
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	375	349
AFS securities allowance for credit losses	0	0
Gross Unrealized Gains	1	3
Gross Unrealized Losses	(25)	(1)
Available-for-sale securities	351	351
U.S. state, municipal and political subdivisions \| Investments, excluding investments in Related Party
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	898	864
AFS securities allowance for credit losses	0	0
Gross Unrealized Gains	115	169
Gross Unrealized Losses	(7)	0
Available-for-sale securities	1,006	1,033
Foreign governments \| Investments, excluding investments in Related Party
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	373	330
AFS securities allowance for credit losses	0	0
Gross Unrealized Gains	18	38
Gross Unrealized Losses	(9)	0
Available-for-sale securities	382	368
Corporate \| Investments, excluding investments in Related Party
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	55,922	51,934
AFS securities allowance for credit losses	(8)	(6)	(15)	0
Gross Unrealized Gains	3,750	6,368
Gross Unrealized Losses	(816)	(116)
Available-for-sale securities	58,848	58,180
CLO \| Investments, excluding investments in Related Party
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	11,299	9,631
AFS securities allowance for credit losses	0	(1)
Gross Unrealized Gains	94	145
Gross Unrealized Losses	(121)	(206)
Available-for-sale securities	11,272	9,569
ABS \| Investments, excluding investments in Related Party
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	4,761	4,259
AFS securities allowance for credit losses	(11)	(6)	(5)	0
Gross Unrealized Gains	152	140
Gross Unrealized Losses	(70)	(123)
Available-for-sale securities	4,832	4,270
CMBS \| Investments, excluding investments in Related Party
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	2,218	2,165
AFS securities allowance for credit losses	(14)	(10)	(4)	0
Gross Unrealized Gains	66	85
Gross Unrealized Losses	(64)	(71)
Available-for-sale securities	2,206	2,169
RMBS \| Investments, excluding investments in Related Party
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	6,344	6,568
AFS securities allowance for credit losses	(78)	(80)	$ (54)	$ (17)
Gross Unrealized Gains	383	447
Gross Unrealized Losses	(22)	(22)
Available-for-sale securities	6,627	6,913
Related Party
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	6,854	6,444
AFS securities allowance for credit losses	0	(1)
Gross Unrealized Gains	99	120
Gross Unrealized Losses	(48)	(43)
Available-for-sale securities	6,905	6,520
Related Party \| Investments, excluding investments in Related Party
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	6,905	6,520
Related Party \| Corporate
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	213	213
AFS securities allowance for credit losses	0	0
Gross Unrealized Gains	8	2
Gross Unrealized Losses	0	0
Available-for-sale securities	221	215
Related Party \| CLO
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	1,864	1,511
AFS securities allowance for credit losses	0	(1)
Gross Unrealized Gains	13	23
Gross Unrealized Losses	(8)	(13)
Available-for-sale securities	1,869	1,520
Related Party \| ABS
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities	4,777	4,720
AFS securities allowance for credit losses	0	0
Gross Unrealized Gains	78	95
Gross Unrealized Losses	(40)	(30)
Available-for-sale securities	$ 4,815	$ 4,785

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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