Fair Value Measurement - Financial Instruments Carried at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Assets:
Other invested assets	$ 181	$ 214
Assets of CIVs	5,271	1,913
Other assets	132	145
Liabilities:
Credit derivative liabilities	156	103
Liabilities of CIVs	4,436	1,590
Fair Value Measured at Net Asset Value
Assets:
Other invested assets	19	91
Recurring
Assets:
Other invested assets	12	15
FG VIEs’ assets	260	296
Assets of CIVs	4,896	1,719
Other assets	132	145
Total assets carried at fair value	14,727	11,799
Liabilities:
Credit derivative liabilities	156	103
FG VIEs’ liabilities	289	333
Liabilities of CIVs	3,849	1,299
Other liabilities	1	1
Total liabilities carried at fair value	4,295	1,736
Recurring | CLO obligations of CFEs
Liabilities:
Liabilities of CIVs	3,665	1,227
Recurring | Warehouse financing debt
Liabilities:
Liabilities of CIVs	126	25
Recurring | Securities sold short
Liabilities:
Liabilities of CIVs	41	47
Recurring | Borrowings
Liabilities:
Liabilities of CIVs	17
Recurring | Level 1
Assets:
Other invested assets	6	10
FG VIEs’ assets	0	0
Assets of CIVs	145	139
Other assets	53	42
Total assets carried at fair value	1,429	977
Liabilities:
Credit derivative liabilities	0	0
FG VIEs’ liabilities	0	0
Liabilities of CIVs	0	0
Other liabilities	0	0
Total liabilities carried at fair value	0	0
Recurring | Level 1 | CLO obligations of CFEs
Liabilities:
Liabilities of CIVs	0	0
Recurring | Level 1 | Warehouse financing debt
Liabilities:
Liabilities of CIVs	0	0
Recurring | Level 1 | Securities sold short
Liabilities:
Liabilities of CIVs	0	0
Recurring | Level 1 | Borrowings
Liabilities:
Liabilities of CIVs	0
Recurring | Level 2
Assets:
Other invested assets	0	0
FG VIEs’ assets	0	0
Assets of CIVs	4,421	1,578
Other assets	54	48
Total assets carried at fair value	11,526	9,138
Liabilities:
Credit derivative liabilities	0	0
FG VIEs’ liabilities	0	0
Liabilities of CIVs	144	72
Other liabilities	1	1
Total liabilities carried at fair value	145	73
Recurring | Level 2 | CLO obligations of CFEs
Liabilities:
Liabilities of CIVs	0	0
Recurring | Level 2 | Warehouse financing debt
Liabilities:
Liabilities of CIVs	103	25
Recurring | Level 2 | Securities sold short
Liabilities:
Liabilities of CIVs	41	47
Recurring | Level 2 | Borrowings
Liabilities:
Liabilities of CIVs	0
Recurring | Level 3
Assets:
Other invested assets	6	5
FG VIEs’ assets	260	296
Assets of CIVs	330	2
Other assets	25	55
Total assets carried at fair value	1,772	1,684
Liabilities:
Credit derivative liabilities	156	103
FG VIEs’ liabilities	289	333
Liabilities of CIVs	3,705	1,227
Other liabilities	0	0
Total liabilities carried at fair value	4,150	1,663
Recurring | Level 3 | CLO obligations of CFEs
Liabilities:
Liabilities of CIVs	3,665	1,227
Recurring | Level 3 | Warehouse financing debt
Liabilities:
Liabilities of CIVs	23	0
Recurring | Level 3 | Securities sold short
Liabilities:
Liabilities of CIVs	0	0
Recurring | Level 3 | Borrowings
Liabilities:
Liabilities of CIVs	17
Fixed-maturity securities
Assets:
Estimated Fair Value	8,202	8,773
Fixed-maturity securities | Obligations of state and political subdivisions
Assets:
Estimated Fair Value	3,660	3,991
Fixed-maturity securities | U.S. government and agencies
Assets:
Estimated Fair Value	128	162
Fixed-maturity securities | Corporate securities
Assets:
Estimated Fair Value	2,605	2,513
Fixed-maturity securities | RMBS
Assets:
Estimated Fair Value	437	566
Fixed-maturity securities | CMBS
Assets:
Estimated Fair Value	346	387
Fixed-maturity securities | Non-U.S. government securities
Assets:
Estimated Fair Value	136	173
Fixed-maturity securities | Recurring
Assets:
Estimated Fair Value	8,202	8,773
Fixed-maturity securities | Recurring | Obligations of state and political subdivisions
Assets:
Estimated Fair Value	3,660	3,991
Fixed-maturity securities | Recurring | U.S. government and agencies
Assets:
Estimated Fair Value	128	162
Fixed-maturity securities | Recurring | Corporate securities
Assets:
Estimated Fair Value	2,605	2,513
Fixed-maturity securities | Recurring | RMBS
Assets:
Estimated Fair Value	437	566
Fixed-maturity securities | Recurring | CMBS
Assets:
Estimated Fair Value	346	387
Fixed-maturity securities | Recurring | Asset-backed securities
Assets:
Estimated Fair Value	890	981
Fixed-maturity securities | Recurring | Non-U.S. government securities
Assets:
Estimated Fair Value	136	173
Fixed-maturity securities | Recurring | Level 1
Assets:
Estimated Fair Value	0	0
Fixed-maturity securities | Recurring | Level 1 | Obligations of state and political subdivisions
Assets:
Estimated Fair Value	0	0
Fixed-maturity securities | Recurring | Level 1 | U.S. government and agencies
Assets:
Estimated Fair Value	0	0
Fixed-maturity securities | Recurring | Level 1 | Corporate securities
Assets:
Estimated Fair Value	0	0
Fixed-maturity securities | Recurring | Level 1 | RMBS
Assets:
Estimated Fair Value	0	0
Fixed-maturity securities | Recurring | Level 1 | CMBS
Assets:
Estimated Fair Value	0	0
Fixed-maturity securities | Recurring | Level 1 | Asset-backed securities
Assets:
Estimated Fair Value	0	0
Fixed-maturity securities | Recurring | Level 1 | Non-U.S. government securities
Assets:
Estimated Fair Value	0	0
Fixed-maturity securities | Recurring | Level 2
Assets:
Estimated Fair Value	7,051	7,447
Fixed-maturity securities | Recurring | Level 2 | Obligations of state and political subdivisions
Assets:
Estimated Fair Value	3,588	3,890
Fixed-maturity securities | Recurring | Level 2 | U.S. government and agencies
Assets:
Estimated Fair Value	128	162
Fixed-maturity securities | Recurring | Level 2 | Corporate securities
Assets:
Estimated Fair Value	2,605	2,483
Fixed-maturity securities | Recurring | Level 2 | RMBS
Assets:
Estimated Fair Value	221	311
Fixed-maturity securities | Recurring | Level 2 | CMBS
Assets:
Estimated Fair Value	346	387
Fixed-maturity securities | Recurring | Level 2 | Asset-backed securities
Assets:
Estimated Fair Value	27	41
Fixed-maturity securities | Recurring | Level 2 | Non-U.S. government securities
Assets:
Estimated Fair Value	136	173
Fixed-maturity securities | Recurring | Level 3
Assets:
Estimated Fair Value	1,151	1,326
Fixed-maturity securities | Recurring | Level 3 | Obligations of state and political subdivisions
Assets:
Estimated Fair Value	72	101
Fixed-maturity securities | Recurring | Level 3 | U.S. government and agencies
Assets:
Estimated Fair Value	0	0
Fixed-maturity securities | Recurring | Level 3 | Corporate securities
Assets:
Estimated Fair Value	0	30
Fixed-maturity securities | Recurring | Level 3 | RMBS
Assets:
Estimated Fair Value	216	255
Fixed-maturity securities | Recurring | Level 3 | CMBS
Assets:
Estimated Fair Value	0	0
Fixed-maturity securities | Recurring | Level 3 | Asset-backed securities
Assets:
Estimated Fair Value	863	940
Fixed-maturity securities | Recurring | Level 3 | Non-U.S. government securities
Assets:
Estimated Fair Value	0	0
Short-term investments | Recurring
Assets:
Estimated Fair Value	1,225	851
Short-term investments | Recurring | Level 1
Assets:
Estimated Fair Value	1,225	786
Short-term investments | Recurring | Level 2
Assets:
Estimated Fair Value	0	65
Short-term investments | Recurring | Level 3
Assets:
Estimated Fair Value	0	0
Fund Investments | Fair Value Measured at Net Asset Value | Equity securities and warrants
Assets:
Assets of CIVs	6	8
Fund Investments | Recurring | Obligations of state and political subdivisions
Assets:
Assets of CIVs	101	61
Fund Investments | Recurring | Corporate securities
Assets:
Assets of CIVs	98	9
Fund Investments | Recurring | Equity securities and warrants
Assets:
Assets of CIVs	246	10
Fund Investments | Recurring | Structured products
Assets:
Assets of CIVs	62	39
Fund Investments | Recurring | Level 1 | Obligations of state and political subdivisions
Assets:
Assets of CIVs	0	0
Fund Investments | Recurring | Level 1 | Corporate securities
Assets:
Assets of CIVs	0	0
Fund Investments | Recurring | Level 1 | Equity securities and warrants
Assets:
Assets of CIVs	0	0
Fund Investments | Recurring | Level 1 | Structured products
Assets:
Assets of CIVs	0	0
Fund Investments | Recurring | Level 2 | Obligations of state and political subdivisions
Assets:
Assets of CIVs	101	61
Fund Investments | Recurring | Level 2 | Corporate securities
Assets:
Assets of CIVs	7	9
Fund Investments | Recurring | Level 2 | Equity securities and warrants
Assets:
Assets of CIVs	7	8
Fund Investments | Recurring | Level 2 | Structured products
Assets:
Assets of CIVs	62	39
Fund Investments | Recurring | Level 3 | Obligations of state and political subdivisions
Assets:
Assets of CIVs	0	0
Fund Investments | Recurring | Level 3 | Corporate securities
Assets:
Assets of CIVs	91	0
Fund Investments | Recurring | Level 3 | Equity securities and warrants
Assets:
Assets of CIVs	239	2
Fund Investments | Recurring | Level 3 | Structured products
Assets:
Assets of CIVs	0	0
CLOs | Recurring | Short-term investments
Assets:
Assets of CIVs	145	139
CLOs | Recurring | Loans
Assets:
Assets of CIVs	4,244	1,461
CLOs | Recurring | Level 1 | Short-term investments
Assets:
Assets of CIVs	145	139
CLOs | Recurring | Level 1 | Loans
Assets:
Assets of CIVs	0	0
CLOs | Recurring | Level 2 | Short-term investments
Assets:
Assets of CIVs	0	0
CLOs | Recurring | Level 2 | Loans
Assets:
Assets of CIVs	4,244	1,461
CLOs | Recurring | Level 3 | Short-term investments
Assets:
Assets of CIVs	0	0
CLOs | Recurring | Level 3 | Loans
Assets:
Assets of CIVs	$ 0	$ 0