Fair Value Measurements (excluding Consolidated Investment Entities) - Level 3 Financial Instruments (Details) - Measured at fair value on a recurring basis - Level 3 - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Embedded derivative on reinsurance
Derivatives Rollforward:
Fair Value, Derivatives, beginning balance	$ (58)	$ (86)	$ (58)	$ (87)
Total Realized/Unrealized Gains (Losses) Included in Net income	0	0	0	1
Total Realized/Unrealized Gains (Losses) Included in OCI	0	0	0	0
Purchases	0	0	0	0
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, Derivatives, ending balance	(58)	(86)	(58)	(86)
Change In Unrealized Gains (Losses) Included in Earnings	0	0	0	0
Change In Unrealized Gains (Losses) Included in OCI	0	0	0	0
Transfers in to Level 3	0	0	0	0
Managed custody guarantees
Derivatives Rollforward:
Fair Value, Derivatives, beginning balance	(3)	(15)	(6)	(20)
Total Realized/Unrealized Gains (Losses) Included in Net income	0	11	4	17
Total Realized/Unrealized Gains (Losses) Included in OCI	0	0	0	0
Purchases	0	0	0	0
Issuances	0	0	(1)	(1)
Sales	0	0	0	0
Settlements	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, Derivatives, ending balance	(3)	(4)	(3)	(4)
Change In Unrealized Gains (Losses) Included in Earnings	0	0	0	0
Change In Unrealized Gains (Losses) Included in OCI	0	0	0	0
Transfers in to Level 3	0	0	0	0
Short-term investments and cash equivalents
Derivatives Rollforward:
Fair Value, Derivatives, beginning balance		8		0
Total Realized/Unrealized Gains (Losses) Included in Net income		0		0
Total Realized/Unrealized Gains (Losses) Included in OCI		0		0
Purchases		0		8
Issuances		0		0
Sales		0		0
Settlements		(8)		(8)
Transfers out of Level 3		0		0
Fair Value, Derivatives, ending balance		0		0
Change In Unrealized Gains (Losses) Included in Earnings		0		0
Change In Unrealized Gains (Losses) Included in OCI		0		0
Transfers in to Level 3		0		0
U.S. corporate public securities
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance		71		16
Total Realized/Unrealized Gains (Losses) Included in Net income		0		0
Total Realized/Unrealized Gains (Losses) Included in OCI		(1)		(1)
Purchases		1		5
Issuances		0		0
Sales		0		0
Settlements		0		0
Transfers out of Level 3		(52)		(1)
Fair Value, Assets, ending balance		19		19
Change In Unrealized Gains (Losses) Included in Earnings		0		0
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI		1		(1)
Transfers in to Level 3		0		0
U.S. corporate public securities | Available-for-sale Securities
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance	21		20
Total Realized/Unrealized Gains (Losses) Included in Net income	0		0
Total Realized/Unrealized Gains (Losses) Included in OCI	(1)		0
Purchases	0		0
Issuances	0		0
Sales	0		0
Settlements	0		0
Transfers out of Level 3	0		0
Fair Value, Assets, ending balance	20		20
Change In Unrealized Gains (Losses) Included in Earnings	0		0
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI	0		0
Transfers in to Level 3	0		0
U.S. corporate private securities
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance		1,925		1,910
Total Realized/Unrealized Gains (Losses) Included in Net income		(1)		(2)
Total Realized/Unrealized Gains (Losses) Included in OCI		(134)		(277)
Purchases		89		158
Issuances		0		0
Sales		0		0
Settlements		(58)		(120)
Transfers out of Level 3		(41)		(10)
Fair Value, Assets, ending balance		1,780		1,780
Change In Unrealized Gains (Losses) Included in Earnings		(1)		(2)
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI		(133)		(276)
Transfers in to Level 3		0		121
U.S. corporate private securities | Available-for-sale Securities
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance	1,800		1,801
Total Realized/Unrealized Gains (Losses) Included in Net income	0		0
Total Realized/Unrealized Gains (Losses) Included in OCI	(29)		6
Purchases	20		61
Issuances	0		0
Sales	(3)		(3)
Settlements	(56)		(133)
Transfers out of Level 3	0		0
Fair Value, Assets, ending balance	1,732		1,732
Change In Unrealized Gains (Losses) Included in Earnings	0		1
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI	(29)		5
Transfers in to Level 3	0		0
Foreign corporate public securities and foreign governments | Available-for-sale Securities
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance		11	3	0
Total Realized/Unrealized Gains (Losses) Included in Net income		0	0	0
Total Realized/Unrealized Gains (Losses) Included in OCI		0	0	0
Purchases		4	0	4
Issuances		0	0	0
Sales		0	0	0
Settlements		0	0	0
Transfers out of Level 3		(11)	(3)	0
Fair Value, Assets, ending balance	0	4	0	4
Change In Unrealized Gains (Losses) Included in Earnings		0	0	0
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI		0	0	0
Transfers in to Level 3		0	0	0
Foreign corporate private securities
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance		496		353
Total Realized/Unrealized Gains (Losses) Included in Net income		(3)		(22)
Total Realized/Unrealized Gains (Losses) Included in OCI		(7)		(31)
Purchases		51		97
Issuances		0		0
Sales		0		0
Settlements		(15)		(28)
Transfers out of Level 3		(119)		(114)
Fair Value, Assets, ending balance		403		403
Change In Unrealized Gains (Losses) Included in Earnings		(4)		(4)
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI		(7)		(31)
Transfers in to Level 3		0		148
Foreign corporate private securities | Available-for-sale Securities
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance	441		432
Total Realized/Unrealized Gains (Losses) Included in Net income	1		3
Total Realized/Unrealized Gains (Losses) Included in OCI	0		7
Purchases	19		75
Issuances	0		0
Sales	0		0
Settlements	(93)		(181)
Transfers out of Level 3	0		0
Fair Value, Assets, ending balance	413		413
Change In Unrealized Gains (Losses) Included in Earnings	1		3
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI	0		6
Transfers in to Level 3	45		77
Residential mortgage-backed securities
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance		45		43
Total Realized/Unrealized Gains (Losses) Included in Net income		(6)		(15)
Total Realized/Unrealized Gains (Losses) Included in OCI		0		0
Purchases		2		4
Issuances		0		0
Sales		0		0
Settlements		(9)		0
Transfers out of Level 3		(2)		(2)
Fair Value, Assets, ending balance		31		31
Change In Unrealized Gains (Losses) Included in Earnings		(6)		(15)
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI		0		0
Transfers in to Level 3		1		1
Residential mortgage-backed securities | Available-for-sale Securities
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance	56		28
Total Realized/Unrealized Gains (Losses) Included in Net income	(3)		(3)
Total Realized/Unrealized Gains (Losses) Included in OCI	0		0
Purchases	4		32
Issuances	0		0
Sales	0		0
Settlements	0		0
Transfers out of Level 3	0		0
Fair Value, Assets, ending balance	57		57
Change In Unrealized Gains (Losses) Included in Earnings	(3)		(3)
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI	0		0
Transfers in to Level 3	0		0
Commercial mortgage-backed securities
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance		49		44
Total Realized/Unrealized Gains (Losses) Included in Net income		0		0
Total Realized/Unrealized Gains (Losses) Included in OCI		(2)		(4)
Purchases		35		39
Issuances		0		0
Sales		0		(10)
Settlements		(5)		(6)
Transfers out of Level 3		(14)		0
Fair Value, Assets, ending balance		63		63
Change In Unrealized Gains (Losses) Included in Earnings		0		0
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI		(2)		(4)
Transfers in to Level 3		0		0
Asset-backed Securities [Member]
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance		2,597		2,366
Total Realized/Unrealized Gains (Losses) Included in Net income		(10)		(39)
Total Realized/Unrealized Gains (Losses) Included in OCI		(144)		(313)
Purchases		182		307
Issuances		0		0
Sales		0		(10)
Settlements		(87)		(154)
Transfers out of Level 3		(239)		(127)
Fair Value, Assets, ending balance		2,300		2,300
Change In Unrealized Gains (Losses) Included in Earnings		(11)		(21)
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI		(143)		(312)
Transfers in to Level 3		1		270
Asset-backed Securities [Member] | Available-for-sale Securities
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance	77		64
Total Realized/Unrealized Gains (Losses) Included in Net income	0		0
Total Realized/Unrealized Gains (Losses) Included in OCI	0		0
Purchases	4		4
Issuances	0		0
Sales	0		0
Settlements	(1)		(1)
Transfers out of Level 3	(35)		(22)
Fair Value, Assets, ending balance	45		45
Change In Unrealized Gains (Losses) Included in Earnings	0		0
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI	0		0
Transfers in to Level 3	0		0
Fixed maturities | Available-for-sale Securities
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance	2,396		2,349
Total Realized/Unrealized Gains (Losses) Included in Net income	(2)		0
Total Realized/Unrealized Gains (Losses) Included in OCI	(30)		13
Purchases	47		172
Issuances	0		0
Sales	(3)		(3)
Settlements	(150)		(315)
Transfers out of Level 3	(35)		(25)
Fair Value, Assets, ending balance	2,268		2,268
Change In Unrealized Gains (Losses) Included in Earnings	(2)		1
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI	(29)		11
Transfers in to Level 3	45		77
Equity securities, at fair value
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance	192	203	196	203
Total Realized/Unrealized Gains (Losses) Included in Net income	0	(17)	(4)	(26)
Total Realized/Unrealized Gains (Losses) Included in OCI	0	0	0	0
Purchases	0	26	0	26
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Transfers out of Level 3	0	(9)	0	0
Fair Value, Assets, ending balance	192	203	192	203
Change In Unrealized Gains (Losses) Included in Earnings	0	(17)	(3)	(26)
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI	0	0	0	0
Transfers in to Level 3	0	0	0	0
US Government Agencies Debt Securities | Available-for-sale Securities
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance	1		1
Total Realized/Unrealized Gains (Losses) Included in Net income	0		0
Total Realized/Unrealized Gains (Losses) Included in OCI	0		0
Purchases	0		0
Issuances	0		0
Sales	0		0
Settlements	0		0
Transfers out of Level 3	0		0
Fair Value, Assets, ending balance	1		1
Change In Unrealized Gains (Losses) Included in Earnings	0		0
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI	0		0
Transfers in to Level 3	0		0
Contingent Consideration
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance	(112)	(11)	(112)	(11)
Total Realized/Unrealized Gains (Losses) Included in Net income	0	0	0	0
Total Realized/Unrealized Gains (Losses) Included in OCI	0	0	0	0
Purchases	0	0	0	0
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, Assets, ending balance	(112)	(11)	(112)	(11)
Change In Unrealized Gains (Losses) Included in Earnings	0	0	0	0
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI	0	0	0	0
Transfers in to Level 3	0	0	0	0
Assets held in separate accounts
Fixed Maturities and Equity Securities Rollforward:
Fair Value, Assets, beginning balance	349	334	347	316
Total Realized/Unrealized Gains (Losses) Included in Net income	(8)	(12)	(4)	(26)
Total Realized/Unrealized Gains (Losses) Included in OCI	0	0	0	0
Purchases	7	67	7	132
Issuances	0	0	0	0
Sales	(7)	(3)	(9)	(4)
Settlements	0	0	0	0
Transfers out of Level 3	0	(37)	0	(75)
Fair Value, Assets, ending balance	344	349	344	349
Change In Unrealized Gains (Losses) Included in Earnings	0	0	0	0
Derivatives Rollforward:
Change In Unrealized Gains (Losses) Included in OCI	0	0	0	0
Transfers in to Level 3	$ 3	$ 0	$ 3	$ 6