Fair Value Measurement - Financial Instruments Carried at Fair Value (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Assets:
Unrealized loss position	$ 9,451	$ 10,122
Other invested assets (includes $15 and $6 measured at fair value)	122	118
Assets of consolidated investment vehicles	1,669	572
Other assets	160	135
Liabilities:
Credit derivative liabilities	163	191
Liabilities of consolidated investment vehicles	1,236	482
Fixed Maturities [Member]
Assets:
Unrealized loss position	8,630	8,854
Fixed Maturities [Member] | Obligations of state and political subdivisions [Member]
Assets:
Unrealized loss position	4,113	4,340
Fixed Maturities [Member] | US government and agencies [Member]
Assets:
Unrealized loss position	174	147
Fixed Maturities [Member] | Corporate securities [Member]
Assets:
Unrealized loss position	2,389	2,221
Fixed Maturities [Member] | RMBS [Member]
Assets:
Unrealized loss position	635	775
Fixed Maturities [Member] | CMBS [Member]
Assets:
Unrealized loss position	411	419
Fixed Maturities [Member] | Asset-backed Securities [Member]
Assets:
Unrealized loss position	768	720
Fixed Maturities [Member] | Foreign government securities [Member]
Assets:
Unrealized loss position	140	232
Short-term Investments [Member]
Assets:
Unrealized loss position	821	1,268
Recurring [Member]
Assets:
Other invested assets (includes $15 and $6 measured at fair value)	15	6
FG VIEs’ assets, at fair value	318	442
Assets of consolidated investment vehicles	1,452	558
Other assets	160	135
Total assets carried at fair value	11,396	11,263
Liabilities:
Credit derivative liabilities	163	191
FG VIEs’ liabilities with recourse, at fair value	332	367
FG VIEs’ liabilities without recourse, at fair value	20	102
Liabilities of consolidated investment vehicles	836
Total liabilities carried at fair value	1,351	1,141
Recurring [Member] | Collateralized Loan Obligations of CFE, At Fair Value [Member]
Liabilities:
Liabilities of consolidated investment vehicles	806	481
Recurring [Member] | Securities Sold Short [Member]
Liabilities:
Liabilities of consolidated investment vehicles	30
Recurring [Member] | Fixed Maturities [Member]
Assets:
Unrealized loss position	8,630	8,854
Recurring [Member] | Fixed Maturities [Member] | Obligations of state and political subdivisions [Member]
Assets:
Unrealized loss position	4,113	4,340
Recurring [Member] | Fixed Maturities [Member] | US government and agencies [Member]
Assets:
Unrealized loss position	174	147
Recurring [Member] | Fixed Maturities [Member] | Corporate securities [Member]
Assets:
Unrealized loss position	2,389	2,221
Recurring [Member] | Fixed Maturities [Member] | RMBS [Member]
Assets:
Unrealized loss position	635	775
Recurring [Member] | Fixed Maturities [Member] | CMBS [Member]
Assets:
Unrealized loss position	411	419
Recurring [Member] | Fixed Maturities [Member] | Asset-backed Securities [Member]
Assets:
Unrealized loss position	768	720
Recurring [Member] | Fixed Maturities [Member] | Foreign government securities [Member]
Assets:
Unrealized loss position	140	232
Recurring [Member] | Short-term Investments [Member]
Assets:
Unrealized loss position	821	1,268
Recurring [Member] | Fund Investments [Member] | Obligations of state and political subdivisions [Member]
Assets:
Assets of consolidated investment vehicles	39
Recurring [Member] | Fund Investments [Member] | Debt Securities [Member]
Assets:
Assets of consolidated investment vehicles	63	47
Recurring [Member] | Fund Investments [Member] | Equity Securities and Warrants [Member]
Assets:
Assets of consolidated investment vehicles	54	17
Recurring [Member] | Fund Investments [Member] | Structured Products [Member]
Assets:
Assets of consolidated investment vehicles	43
Recurring [Member] | CLO Investments [Member] | Debt Securities [Member]
Assets:
Assets of consolidated investment vehicles	850	494
Recurring [Member] | CLO Investments [Member] | Short-term Investments [Member]
Assets:
Assets of consolidated investment vehicles	403
Recurring [Member] | Level 1 [Member]
Assets:
Other invested assets (includes $15 and $6 measured at fair value)	9	0
FG VIEs’ assets, at fair value	0	0
Assets of consolidated investment vehicles	403	0
Other assets	41	32
Total assets carried at fair value	1,207	1,093
Liabilities:
Credit derivative liabilities	0	0
FG VIEs’ liabilities with recourse, at fair value	0	0
FG VIEs’ liabilities without recourse, at fair value	0	0
Liabilities of consolidated investment vehicles	0
Total liabilities carried at fair value	0	0
Recurring [Member] | Level 1 [Member] | Collateralized Loan Obligations of CFE, At Fair Value [Member]
Liabilities:
Liabilities of consolidated investment vehicles	0	0
Recurring [Member] | Level 1 [Member] | Securities Sold Short [Member]
Liabilities:
Liabilities of consolidated investment vehicles	0
Recurring [Member] | Level 1 [Member] | Fixed Maturities [Member]
Assets:
Unrealized loss position	0	0
Recurring [Member] | Level 1 [Member] | Fixed Maturities [Member] | Obligations of state and political subdivisions [Member]
Assets:
Unrealized loss position	0	0
Recurring [Member] | Level 1 [Member] | Fixed Maturities [Member] | US government and agencies [Member]
Assets:
Unrealized loss position	0	0
Recurring [Member] | Level 1 [Member] | Fixed Maturities [Member] | Corporate securities [Member]
Assets:
Unrealized loss position	0	0
Recurring [Member] | Level 1 [Member] | Fixed Maturities [Member] | RMBS [Member]
Assets:
Unrealized loss position	0	0
Recurring [Member] | Level 1 [Member] | Fixed Maturities [Member] | CMBS [Member]
Assets:
Unrealized loss position	0	0
Recurring [Member] | Level 1 [Member] | Fixed Maturities [Member] | Asset-backed Securities [Member]
Assets:
Unrealized loss position	0	0
Recurring [Member] | Level 1 [Member] | Fixed Maturities [Member] | Foreign government securities [Member]
Assets:
Unrealized loss position	0	0
Recurring [Member] | Level 1 [Member] | Short-term Investments [Member]
Assets:
Unrealized loss position	754	1,061
Recurring [Member] | Level 1 [Member] | Fund Investments [Member] | Obligations of state and political subdivisions [Member]
Assets:
Assets of consolidated investment vehicles	0
Recurring [Member] | Level 1 [Member] | Fund Investments [Member] | Debt Securities [Member]
Assets:
Assets of consolidated investment vehicles	0	0
Recurring [Member] | Level 1 [Member] | Fund Investments [Member] | Equity Securities and Warrants [Member]
Assets:
Assets of consolidated investment vehicles	0	0
Recurring [Member] | Level 1 [Member] | Fund Investments [Member] | Structured Products [Member]
Assets:
Assets of consolidated investment vehicles	0
Recurring [Member] | Level 1 [Member] | CLO Investments [Member] | Debt Securities [Member]
Assets:
Assets of consolidated investment vehicles	0	0
Recurring [Member] | Level 1 [Member] | CLO Investments [Member] | Short-term Investments [Member]
Assets:
Assets of consolidated investment vehicles	403
Recurring [Member] | Level 2 [Member]
Assets:
Other invested assets (includes $15 and $6 measured at fair value)	0	0
FG VIEs’ assets, at fair value	0	0
Assets of consolidated investment vehicles	930	494
Other assets	42	45
Total assets carried at fair value	8,575	8,486
Liabilities:
Credit derivative liabilities	0	0
FG VIEs’ liabilities with recourse, at fair value	0	0
FG VIEs’ liabilities without recourse, at fair value	0	0
Liabilities of consolidated investment vehicles	30
Total liabilities carried at fair value	30	0
Recurring [Member] | Level 2 [Member] | Collateralized Loan Obligations of CFE, At Fair Value [Member]
Liabilities:
Liabilities of consolidated investment vehicles	0	0
Recurring [Member] | Level 2 [Member] | Securities Sold Short [Member]
Liabilities:
Liabilities of consolidated investment vehicles	30
Recurring [Member] | Level 2 [Member] | Fixed Maturities [Member]
Assets:
Unrealized loss position	7,536	7,740
Recurring [Member] | Level 2 [Member] | Fixed Maturities [Member] | Obligations of state and political subdivisions [Member]
Assets:
Unrealized loss position	4,016	4,233
Recurring [Member] | Level 2 [Member] | Fixed Maturities [Member] | US government and agencies [Member]
Assets:
Unrealized loss position	174	147
Recurring [Member] | Level 2 [Member] | Fixed Maturities [Member] | Corporate securities [Member]
Assets:
Unrealized loss position	2,360	2,180
Recurring [Member] | Level 2 [Member] | Fixed Maturities [Member] | RMBS [Member]
Assets:
Unrealized loss position	381	467
Recurring [Member] | Level 2 [Member] | Fixed Maturities [Member] | CMBS [Member]
Assets:
Unrealized loss position	411	419
Recurring [Member] | Level 2 [Member] | Fixed Maturities [Member] | Asset-backed Securities [Member]
Assets:
Unrealized loss position	54	62
Recurring [Member] | Level 2 [Member] | Fixed Maturities [Member] | Foreign government securities [Member]
Assets:
Unrealized loss position	140	232
Recurring [Member] | Level 2 [Member] | Short-term Investments [Member]
Assets:
Unrealized loss position	67	207
Recurring [Member] | Level 2 [Member] | Fund Investments [Member] | Obligations of state and political subdivisions [Member]
Assets:
Assets of consolidated investment vehicles	39
Recurring [Member] | Level 2 [Member] | Fund Investments [Member] | Debt Securities [Member]
Assets:
Assets of consolidated investment vehicles	3	0
Recurring [Member] | Level 2 [Member] | Fund Investments [Member] | Equity Securities and Warrants [Member]
Assets:
Assets of consolidated investment vehicles	1	0
Recurring [Member] | Level 2 [Member] | Fund Investments [Member] | Structured Products [Member]
Assets:
Assets of consolidated investment vehicles	37
Recurring [Member] | Level 2 [Member] | CLO Investments [Member] | Debt Securities [Member]
Assets:
Assets of consolidated investment vehicles	850	494
Recurring [Member] | Level 2 [Member] | CLO Investments [Member] | Short-term Investments [Member]
Assets:
Assets of consolidated investment vehicles	0
Recurring [Member] | Level 3 [Member]
Assets:
Other invested assets (includes $15 and $6 measured at fair value)	6	6
FG VIEs’ assets, at fair value	318	442
Assets of consolidated investment vehicles	119	64
Other assets	77	58
Total assets carried at fair value	1,614	1,684
Liabilities:
Credit derivative liabilities	163	191
FG VIEs’ liabilities with recourse, at fair value	332	367
FG VIEs’ liabilities without recourse, at fair value	20	102
Liabilities of consolidated investment vehicles	806
Total liabilities carried at fair value	1,321	1,141
Recurring [Member] | Level 3 [Member] | Collateralized Loan Obligations of CFE, At Fair Value [Member]
Liabilities:
Liabilities of consolidated investment vehicles	806	481
Recurring [Member] | Level 3 [Member] | Securities Sold Short [Member]
Liabilities:
Liabilities of consolidated investment vehicles	0
Recurring [Member] | Level 3 [Member] | Fixed Maturities [Member]
Assets:
Unrealized loss position	1,094	1,114
Recurring [Member] | Level 3 [Member] | Fixed Maturities [Member] | Obligations of state and political subdivisions [Member]
Assets:
Unrealized loss position	97	107
Recurring [Member] | Level 3 [Member] | Fixed Maturities [Member] | US government and agencies [Member]
Assets:
Unrealized loss position	0	0
Recurring [Member] | Level 3 [Member] | Fixed Maturities [Member] | Corporate securities [Member]
Assets:
Unrealized loss position	29	41
Recurring [Member] | Level 3 [Member] | Fixed Maturities [Member] | RMBS [Member]
Assets:
Unrealized loss position	254	308
Recurring [Member] | Level 3 [Member] | Fixed Maturities [Member] | CMBS [Member]
Assets:
Unrealized loss position	0	0
Recurring [Member] | Level 3 [Member] | Fixed Maturities [Member] | Asset-backed Securities [Member]
Assets:
Unrealized loss position	714	658
Recurring [Member] | Level 3 [Member] | Fixed Maturities [Member] | Foreign government securities [Member]
Assets:
Unrealized loss position	0	0
Recurring [Member] | Level 3 [Member] | Short-term Investments [Member]
Assets:
Unrealized loss position	0	0
Recurring [Member] | Level 3 [Member] | Fund Investments [Member] | Obligations of state and political subdivisions [Member]
Assets:
Assets of consolidated investment vehicles	0
Recurring [Member] | Level 3 [Member] | Fund Investments [Member] | Debt Securities [Member]
Assets:
Assets of consolidated investment vehicles	60	47
Recurring [Member] | Level 3 [Member] | Fund Investments [Member] | Equity Securities and Warrants [Member]
Assets:
Assets of consolidated investment vehicles	53	17
Recurring [Member] | Level 3 [Member] | Fund Investments [Member] | Structured Products [Member]
Assets:
Assets of consolidated investment vehicles	6
Recurring [Member] | Level 3 [Member] | CLO Investments [Member] | Debt Securities [Member]
Assets:
Assets of consolidated investment vehicles	0	$ 0
Recurring [Member] | Level 3 [Member] | CLO Investments [Member] | Short-term Investments [Member]
Assets:
Assets of consolidated investment vehicles	$ 0