Fair Value Measurements - Assets and liabilities measured at fair value on a recurring basis (Details) - USD ($)		Sep. 30, 2022	Dec. 31, 2021
Assets:
Bonds available for sale	[1]	$ 219,767,000,000	$ 277,202,000,000
Other bond securities	[1]	7,131,000,000	6,278,000,000
Equity securities	[1]	608,000,000	739,000,000
Derivative assets		6,744,000,000	5,761,000,000
Counterparty netting		(3,170,000,000)	(2,779,000,000)
Cash Collateral		(3,181,000,000)	(2,139,000,000)
Total derivative assets		393,000,000	843,000,000
Short-term investments	[1]	14,663,000,000	13,357,000,000
Separate account assets		81,302,000,000	109,111,000,000
Liabilities:
Policyholder contract deposits		157,612,000,000	156,686,000,000
Derivative liabilities		5,709,000,000	4,454,000,000
Counterparty netting		(3,170,000,000)	(2,779,000,000)
Cash Collateral		(2,263,000,000)	(1,089,000,000)
Total derivative liabilities		276,000,000	586,000,000
Fortitude Re funds withheld payable		30,424,000,000	40,771,000,000
U.S. government and government sponsored entities
Assets:
Bonds available for sale		7,950,000,000	8,194,000,000
Obligations of states, municipalities and political subdivisions
Assets:
Bonds available for sale		11,891,000,000	14,527,000,000
Non-U.S. governments
Assets:
Bonds available for sale		13,007,000,000	16,330,000,000
Corporate debt
Assets:
Bonds available for sale		133,336,000,000	175,608,000,000
RMBS
Assets:
Bonds available for sale		18,507,000,000	27,287,000,000
CMBS
Assets:
Bonds available for sale		13,931,000,000	15,809,000,000
CDO/ABS
Assets:
Bonds available for sale		21,145,000,000	19,447,000,000
Level 3 | Obligations of states, municipalities and political subdivisions
Assets:
Bonds available for sale		815,000,000	1,400,000,000
Level 3 | Corporate debt
Assets:
Bonds available for sale		2,059,000,000	1,561,000,000
Level 3 | RMBS
Assets:
Bonds available for sale		5,530,000,000	9,916,000,000
Level 3 | CMBS
Assets:
Bonds available for sale		553,000,000	580,000,000
Fair Value Measured at Net Asset Value Per Share
Liabilities:
Fair Value Using NAV Per Share (or its equivalent)		9,800,000,000	8,400,000,000
Recurring Basis
Assets:
Counterparty netting		(3,170,000,000)	(2,779,000,000)
Cash Collateral		(3,181,000,000)	(2,139,000,000)
Counterparty netting and cash collateral		(6,351,000,000)	(4,918,000,000)
Total derivative assets		393,000,000	843,000,000
Short-term investments		5,344,000,000	4,426,000,000
Liabilities:
Policyholder contract deposits		6,385,000,000	9,736,000,000
Counterparty netting		(3,170,000,000)	(2,779,000,000)
Cash Collateral		(2,263,000,000)	(1,089,000,000)
Counterparty netting and cash collateral		(5,433,000,000)	(3,868,000,000)
Total derivative liabilities		276,000,000	586,000,000
Fortitude Re funds withheld payable		(2,505,000,000)
Fortitude Re funds withheld payable			5,922,000,000
Long-term debt		1,613,000,000	1,871,000,000
Recurring Basis | Levels 1, 2 and 3
Assets:
Bonds available for sale		219,767,000,000	277,202,000,000
Other bond securities		7,131,000,000	6,278,000,000
Equity securities		608,000,000	739,000,000
Other invested assets		2,088,000,000	2,086,000,000
Short-term investments		5,344,000,000	4,426,000,000
Other assets		107,000,000	114,000,000
Separate account assets		81,302,000,000	109,111,000,000
Total		316,740,000,000	400,799,000,000
Liabilities:
Policyholder contract deposits		6,385,000,000	9,736,000,000
Fortitude Re funds withheld payable		(2,505,000,000)
Fortitude Re funds withheld payable			5,922,000,000
Long-term debt		1,613,000,000	1,871,000,000
Total		5,769,000,000	18,115,000,000
Recurring Basis | Levels 1, 2 and 3 | Interest rate contracts
Assets:
Derivative assets		3,356,000,000	3,873,000,000
Liabilities:
Derivative liabilities		4,856,000,000	3,633,000,000
Recurring Basis | Levels 1, 2 and 3 | Foreign exchange contracts
Assets:
Derivative assets		2,788,000,000	1,189,000,000
Liabilities:
Derivative liabilities		727,000,000	721,000,000
Recurring Basis | Levels 1, 2 and 3 | Equity contracts
Assets:
Derivative assets		565,000,000	681,000,000
Liabilities:
Derivative liabilities		84,000,000	53,000,000
Recurring Basis | Levels 1, 2 and 3 | Commodity contracts
Assets:
Derivative assets		18,000,000	4,000,000
Recurring Basis | Levels 1, 2 and 3 | Credit contracts
Assets:
Derivative assets		1,000,000	1,000,000
Liabilities:
Derivative liabilities		42,000,000	47,000,000
Recurring Basis | Levels 1, 2 and 3 | Other contracts
Assets:
Derivative assets		16,000,000	13,000,000
Recurring Basis | Levels 1, 2 and 3 | U.S. government and government sponsored entities
Assets:
Bonds available for sale		7,950,000,000	8,194,000,000
Other bond securities		1,565,000,000	1,750,000,000
Recurring Basis | Levels 1, 2 and 3 | Obligations of states, municipalities and political subdivisions
Assets:
Bonds available for sale		11,891,000,000	14,527,000,000
Other bond securities		111,000,000	97,000,000
Recurring Basis | Levels 1, 2 and 3 | Non-U.S. governments
Assets:
Bonds available for sale		13,007,000,000	16,330,000,000
Other bond securities		64,000,000	76,000,000
Recurring Basis | Levels 1, 2 and 3 | Corporate debt
Assets:
Bonds available for sale		133,336,000,000	175,608,000,000
Other bond securities		2,034,000,000	1,050,000,000
Recurring Basis | Levels 1, 2 and 3 | RMBS
Assets:
Bonds available for sale		18,507,000,000	27,287,000,000
Other bond securities		341,000,000	411,000,000
Recurring Basis | Levels 1, 2 and 3 | CMBS
Assets:
Bonds available for sale		13,931,000,000	15,809,000,000
Other bond securities		391,000,000	315,000,000
Recurring Basis | Levels 1, 2 and 3 | CDO/ABS
Assets:
Bonds available for sale		21,145,000,000	19,447,000,000
Other bond securities		2,625,000,000	2,579,000,000
Recurring Basis | Level 1
Assets:
Bonds available for sale		116,000,000	2,562,000,000
Other bond securities		0	0
Equity securities		481,000,000	669,000,000
Other invested assets		0	0
Derivative assets		18,000,000	7,000,000
Short-term investments		3,405,000,000	2,584,000,000
Other assets		0	0
Separate account assets		77,683,000,000	105,221,000,000
Total		81,703,000,000	111,043,000,000
Liabilities:
Policyholder contract deposits		0	0
Derivative liabilities		4,000,000	2,000,000
Fortitude Re funds withheld payable		0
Fortitude Re funds withheld payable			0
Long-term debt		0	0
Total		4,000,000	2,000,000
Recurring Basis | Level 1 | Interest rate contracts
Assets:
Derivative assets		4,000,000	0
Liabilities:
Derivative liabilities		0	1,000,000
Recurring Basis | Level 1 | Foreign exchange contracts
Assets:
Derivative assets		0	0
Liabilities:
Derivative liabilities		0	0
Recurring Basis | Level 1 | Equity contracts
Assets:
Derivative assets		14,000,000	7,000,000
Liabilities:
Derivative liabilities		4,000,000	1,000,000
Recurring Basis | Level 1 | Commodity contracts
Assets:
Derivative assets		0	0
Recurring Basis | Level 1 | Credit contracts
Assets:
Derivative assets		0	0
Liabilities:
Derivative liabilities		0	0
Recurring Basis | Level 1 | Other contracts
Assets:
Derivative assets		0	0
Recurring Basis | Level 1 | U.S. government and government sponsored entities
Assets:
Bonds available for sale		5,000,000	2,553,000,000
Other bond securities		0	0
Recurring Basis | Level 1 | Obligations of states, municipalities and political subdivisions
Assets:
Bonds available for sale		0	0
Other bond securities		0	0
Recurring Basis | Level 1 | Non-U.S. governments
Assets:
Bonds available for sale		111,000,000	9,000,000
Other bond securities		0	0
Recurring Basis | Level 1 | Corporate debt
Assets:
Bonds available for sale		0	0
Other bond securities		0	0
Recurring Basis | Level 1 | RMBS
Assets:
Bonds available for sale		0	0
Other bond securities		0	0
Recurring Basis | Level 1 | CMBS
Assets:
Bonds available for sale		0	0
Other bond securities		0	0
Recurring Basis | Level 1 | CDO/ABS
Assets:
Bonds available for sale		0	0
Other bond securities		0	0
Recurring Basis | Level 2
Assets:
Bonds available for sale		194,441,000,000	247,778,000,000
Other bond securities		4,086,000,000	3,581,000,000
Equity securities		93,000,000	64,000,000
Other invested assets		130,000,000	138,000,000
Derivative assets		6,340,000,000	5,289,000,000
Short-term investments		1,939,000,000	1,842,000,000
Other assets		0	0
Separate account assets		3,619,000,000	3,890,000,000
Total		210,648,000,000	262,582,000,000
Liabilities:
Policyholder contract deposits		37,000,000	54,000,000
Derivative liabilities		5,668,000,000	4,415,000,000
Fortitude Re funds withheld payable		0
Fortitude Re funds withheld payable			0
Long-term debt		1,613,000,000	1,871,000,000
Total		7,318,000,000	6,340,000,000
Recurring Basis | Level 2 | Interest rate contracts
Assets:
Derivative assets		3,142,000,000	3,873,000,000
Liabilities:
Derivative liabilities		4,856,000,000	3,632,000,000
Recurring Basis | Level 2 | Foreign exchange contracts
Assets:
Derivative assets		2,788,000,000	1,188,000,000
Liabilities:
Derivative liabilities		726,000,000	721,000,000
Recurring Basis | Level 2 | Equity contracts
Assets:
Derivative assets		392,000,000	224,000,000
Liabilities:
Derivative liabilities		76,000,000	46,000,000
Recurring Basis | Level 2 | Commodity contracts
Assets:
Derivative assets		18,000,000	4,000,000
Recurring Basis | Level 2 | Credit contracts
Assets:
Derivative assets		0	0
Liabilities:
Derivative liabilities		10,000,000	16,000,000
Recurring Basis | Level 2 | Other contracts
Assets:
Derivative assets		0	0
Recurring Basis | Level 2 | U.S. government and government sponsored entities
Assets:
Bonds available for sale		7,945,000,000	5,641,000,000
Other bond securities		1,565,000,000	1,750,000,000
Recurring Basis | Level 2 | Obligations of states, municipalities and political subdivisions
Assets:
Bonds available for sale		11,077,000,000	13,096,000,000
Other bond securities		111,000,000	97,000,000
Recurring Basis | Level 2 | Non-U.S. governments
Assets:
Bonds available for sale		12,887,000,000	16,314,000,000
Other bond securities		64,000,000	76,000,000
Recurring Basis | Level 2 | Corporate debt
Assets:
Bonds available for sale		129,419,000,000	172,967,000,000
Other bond securities		1,485,000,000	916,000,000
Recurring Basis | Level 2 | RMBS
Assets:
Bonds available for sale		10,626,000,000	16,909,000,000
Other bond securities		130,000,000	215,000,000
Recurring Basis | Level 2 | CMBS
Assets:
Bonds available for sale		13,125,000,000	14,619,000,000
Other bond securities		362,000,000	280,000,000
Recurring Basis | Level 2 | CDO/ABS
Assets:
Bonds available for sale		9,362,000,000	8,232,000,000
Other bond securities		369,000,000	247,000,000
Recurring Basis | Level 3
Assets:
Bonds available for sale		25,210,000,000	26,862,000,000
Other bond securities		3,045,000,000	2,697,000,000
Equity securities		34,000,000	6,000,000
Other invested assets		1,958,000,000	1,948,000,000
Derivative assets		386,000,000	465,000,000
Short-term investments		0	0
Other assets		107,000,000	114,000,000
Separate account assets		0	0
Total		30,740,000,000	32,092,000,000
Liabilities:
Policyholder contract deposits		6,348,000,000	9,682,000,000
Derivative liabilities		37,000,000	37,000,000
Fortitude Re funds withheld payable		(2,505,000,000)
Fortitude Re funds withheld payable			5,922,000,000
Long-term debt		0	0
Total		3,880,000,000	15,641,000,000
Recurring Basis | Level 3 | Interest rate contracts
Assets:
Derivative assets		210,000,000	0
Liabilities:
Derivative liabilities		0	0
Recurring Basis | Level 3 | Foreign exchange contracts
Assets:
Derivative assets		0	1,000,000
Liabilities:
Derivative liabilities		1,000,000	0
Recurring Basis | Level 3 | Equity contracts
Assets:
Derivative assets		159,000,000	450,000,000
Liabilities:
Derivative liabilities		4,000,000	6,000,000
Recurring Basis | Level 3 | Commodity contracts
Assets:
Derivative assets		0	0
Recurring Basis | Level 3 | Credit contracts
Assets:
Derivative assets		1,000,000	1,000,000
Liabilities:
Derivative liabilities		32,000,000	31,000,000
Recurring Basis | Level 3 | Other contracts
Assets:
Derivative assets		16,000,000	13,000,000
Recurring Basis | Level 3 | U.S. government and government sponsored entities
Assets:
Bonds available for sale		0	0
Other bond securities		0	0
Recurring Basis | Level 3 | Obligations of states, municipalities and political subdivisions
Assets:
Bonds available for sale		814,000,000	1,431,000,000
Other bond securities		0	0
Recurring Basis | Level 3 | Non-U.S. governments
Assets:
Bonds available for sale		9,000,000	7,000,000
Other bond securities		0	0
Recurring Basis | Level 3 | Corporate debt
Assets:
Bonds available for sale		3,917,000,000	2,641,000,000
Other bond securities		549,000,000	134,000,000
Recurring Basis | Level 3 | RMBS
Assets:
Bonds available for sale		7,881,000,000	10,378,000,000
Other bond securities		211,000,000	196,000,000
Recurring Basis | Level 3 | CMBS
Assets:
Bonds available for sale		806,000,000	1,190,000,000
Other bond securities		29,000,000	35,000,000
Recurring Basis | Level 3 | CDO/ABS
Assets:
Bonds available for sale		11,783,000,000	11,215,000,000
Other bond securities		$ 2,256,000,000	$ 2,332,000,000

[1] See Note 8 for details of balances associated with variable interest entities.