Fair Value Measurement - Quantitative Information - Assets & Liabilities (Details) - Level 3 - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Credit derivative liabilities, net
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Internal floor (in bps)	0.00100	0.00100
Valuation, Income Approach | Credit derivative liabilities, net
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value	$ (39)	$ (50)
Valuation, Income Approach | FG VIEs' assets
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value	$ (399)	$ (554)
Minimum | Credit derivative liabilities, net
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Hedge cost (in bps)	0.087%	0.102%
Bank profit (as a percent)	0.836%	1.056%
Minimum | Valuation, Income Approach | FG VIEs' assets
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	4.80%	5.00%
Maximum | Credit derivative liabilities, net
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Hedge cost (in bps)	0.206%	0.265%
Bank profit (as a percent)	2.683%	3.026%
Maximum | Valuation, Income Approach | FG VIEs' assets
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	10.80%	10.70%
Weighted Average | Credit derivative liabilities, net
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Hedge cost (in bps)	0.125%	0.158%
Bank profit (as a percent)	1.394%	1.586%
Weighted Average | Valuation, Income Approach | FG VIEs' assets
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	5.90%	5.80%
CPR | Minimum | Valuation, Income Approach | FG VIEs' assets
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	0.20%	0.20%
CPR | Maximum | Valuation, Income Approach | FG VIEs' assets
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	21.60%	21.40%
CPR | Weighted Average | Valuation, Income Approach | FG VIEs' assets
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	7.60%	7.80%
CDR | Minimum | Valuation, Income Approach | FG VIEs' assets
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	1.30%	1.30%
CDR | Maximum | Valuation, Income Approach | FG VIEs' assets
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	41.00%	41.00%
CDR | Weighted Average | Valuation, Income Approach | FG VIEs' assets
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	10.50%	10.40%
Loss severity | Minimum | Valuation, Income Approach | FG VIEs' assets
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	45.00%	45.00%
Loss severity | Maximum | Valuation, Income Approach | FG VIEs' assets
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	100.00%	100.00%
Loss severity | Weighted Average | Valuation, Income Approach | FG VIEs' assets
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	82.90%	82.90%
Obligations of state and political subdivisions | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total assets carried at fair value	$ 6	$ 6
Obligations of state and political subdivisions | Minimum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	7.00%	7.40%
Obligations of state and political subdivisions | Maximum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	22.50%	22.50%
Obligations of state and political subdivisions | Weighted Average | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	7.80%	7.80%
RMBS | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total assets carried at fair value	$ 153	$ 154
RMBS | Minimum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	7.60%	7.50%
RMBS | Maximum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	11.40%	11.30%
RMBS | Weighted Average | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	9.00%	8.90%
RMBS | CPR | Minimum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	0.90%	0.10%
RMBS | CPR | Maximum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	15.00%	15.00%
RMBS | CPR | Weighted Average | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	3.20%	3.40%
RMBS | CDR | Minimum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	1.50%	1.50%
RMBS | CDR | Maximum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	18.80%	18.80%
RMBS | CDR | Weighted Average | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	5.70%	5.60%
RMBS | Loss severity | Minimum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	50.00%	50.00%
RMBS | Loss severity | Maximum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	125.00%	125.00%
RMBS | Loss severity | Weighted Average | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	81.60%	82.60%
CLOs | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total assets carried at fair value	$ 439	$ 450
CLOs | Discount margin | Minimum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	1.00%	1.10%
CLOs | Discount margin | Maximum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	9.60%	9.50%
CLOs | Discount margin | Weighted Average | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	2.50%	2.60%
Others | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total assets carried at fair value	$ 382	$ 353
Others | Minimum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	6.60%	6.20%
Others | Maximum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	10.10%	11.70%
Others | Weighted Average | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	7.80%	7.80%
FG VIEs' assets | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total assets carried at fair value	$ 167	$ 174
FG VIEs' assets | Minimum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	5.70%	5.50%
FG VIEs' assets | Maximum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	10.80%	10.90%
FG VIEs' assets | Weighted Average | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	9.50%	9.40%
FG VIEs' assets | CPR | Minimum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	0.20%	0.20%
FG VIEs' assets | CPR | Maximum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	21.60%	21.40%
FG VIEs' assets | CPR | Weighted Average | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	7.60%	7.80%
FG VIEs' assets | CDR | Minimum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	1.30%	1.30%
FG VIEs' assets | CDR | Maximum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	41.00%	41.00%
FG VIEs' assets | CDR | Weighted Average | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	10.50%	10.40%
FG VIEs' assets | Loss severity | Minimum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	45.00%	45.00%
FG VIEs' assets | Loss severity | Maximum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	100.00%	100.00%
FG VIEs' assets | Loss severity | Weighted Average | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Conditional prepayment rate	82.90%	82.90%
Structured products | Minimum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	9.80%
Structured products | Maximum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	23.50%
Structured products | Weighted Average | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	16.60%
Other assets | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total assets carried at fair value	$ 3	$ 13
Term (years)	10 years	10 years
Other assets | Minimum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	7.50%	14.70%
Year 1 loss estimates		7.80%
Other assets | Maximum | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	8.00%	21.40%
Year 1 loss estimates		8.40%
Other assets | Weighted Average | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	7.80%	18.00%
Year 1 loss estimates		8.10%
Consolidated Investment Vehicles | Valuation, Income Approach | Equity securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total assets carried at fair value	$ 89	$ 80
Consolidated Investment Vehicles | Valuation, Income Approach | Structured products
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total assets carried at fair value	$ 220	$ 189
Consolidated Investment Vehicles | Discount margin | Valuation, Income Approach | Equity securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)		20.90%
Consolidated Investment Vehicles | Discount margin | Minimum | Valuation, Income Approach | Equity securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	16.50%
Consolidated Investment Vehicles | Discount margin | Maximum | Valuation, Income Approach | Equity securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	23.50%
Consolidated Investment Vehicles | Discount margin | Weighted Average | Valuation, Income Approach | Equity securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	20.50%
Consolidated Investment Vehicles | Terminal growth rate | Valuation, Income Approach | Equity securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	4.00%	4.00%
Consolidated Investment Vehicles | Measurement input, revenue multiple | Valuation, Market Approach | Equity securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Market multiple-price to book	105.00%	110.00%
Exit multiple-price to earnings	525.00%	550.00%
Consolidated Investment Vehicles | Exit multiple-price to book | Valuation, Market Approach | Equity securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	110.00%	110.00%
Consolidated Investment Vehicles | Exit multiple-price to earnings | Valuation, Market Approach | Equity securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Yield (as a percent)	525.00%	550.00%
Other invested assets | Valuation, Income Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total assets carried at fair value	$ 4	$ 3