Investments (excluding Consolidated Investment Entities) - Unrealized Capital Losses (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Available-for-sale Securities, Including Securities Pledged [Line Items]
Twelve Months or Less Below Amortized Cost, Fair Value	$ 3,057	$ 1,221
Twelve Months or Less Below Amortized Cost, Unrealized Capital Losses	107	42
More Than Twelve Months Below Amortized Cost, Fair Value	14,784	18,938
More Than Twelve Months Below Amortized Cost, Unrealized Capital Losses	2,739	2,680
Total, Fair Value	17,841	20,159
Total, Unrealized Capital Losses	$ 2,846	2,722
Minimum
Available-for-sale Securities, Including Securities Pledged [Line Items]
Fixed Maturities Average Duration	6 years
Maximum
Available-for-sale Securities, Including Securities Pledged [Line Items]
Fixed Maturities Average Duration	6 years 6 months
U.S. Treasuries
Available-for-sale Securities, Including Securities Pledged [Line Items]
Twelve Months or Less Below Amortized Cost, Fair Value	$ 304	99
Twelve Months or Less Below Amortized Cost, Unrealized Capital Losses	20	3
More Than Twelve Months Below Amortized Cost, Fair Value	133	109
More Than Twelve Months Below Amortized Cost, Unrealized Capital Losses	32	18
Total, Fair Value	437	208
Total, Unrealized Capital Losses	52	21
U.S. Government agencies and authorities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Twelve Months or Less Below Amortized Cost, Fair Value	14	0
Twelve Months or Less Below Amortized Cost, Unrealized Capital Losses	0	0
More Than Twelve Months Below Amortized Cost, Fair Value	0	3
More Than Twelve Months Below Amortized Cost, Unrealized Capital Losses	0	1
Total, Fair Value	14	3
Total, Unrealized Capital Losses	0	1
State, municipalities, and political subdivisions
Available-for-sale Securities, Including Securities Pledged [Line Items]
Twelve Months or Less Below Amortized Cost, Fair Value	7	20
Twelve Months or Less Below Amortized Cost, Unrealized Capital Losses	0	0
More Than Twelve Months Below Amortized Cost, Fair Value	562	731
More Than Twelve Months Below Amortized Cost, Unrealized Capital Losses	117	101
Total, Fair Value	569	751
Total, Unrealized Capital Losses	117	101
U.S. corporate public securities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Twelve Months or Less Below Amortized Cost, Fair Value	818	321
Twelve Months or Less Below Amortized Cost, Unrealized Capital Losses	35	17
More Than Twelve Months Below Amortized Cost, Fair Value	4,215	5,101
More Than Twelve Months Below Amortized Cost, Unrealized Capital Losses	1,019	887
Total, Fair Value	5,033	5,422
Total, Unrealized Capital Losses	1,054	904
U.S. corporate private securities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Twelve Months or Less Below Amortized Cost, Fair Value	546	176
Twelve Months or Less Below Amortized Cost, Unrealized Capital Losses	13	7
More Than Twelve Months Below Amortized Cost, Fair Value	2,845	3,365
More Than Twelve Months Below Amortized Cost, Unrealized Capital Losses	316	317
Total, Fair Value	3,391	3,541
Total, Unrealized Capital Losses	329	324
Foreign corporate public securities and foreign governments
Available-for-sale Securities, Including Securities Pledged [Line Items]
Twelve Months or Less Below Amortized Cost, Fair Value	450	82
Twelve Months or Less Below Amortized Cost, Unrealized Capital Losses	17	2
More Than Twelve Months Below Amortized Cost, Fair Value	1,285	1,749
More Than Twelve Months Below Amortized Cost, Unrealized Capital Losses	270	268
Total, Fair Value	1,735	1,831
Total, Unrealized Capital Losses	287	270
Foreign corporate private securities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Twelve Months or Less Below Amortized Cost, Fair Value	490	189
Twelve Months or Less Below Amortized Cost, Unrealized Capital Losses	12	5
More Than Twelve Months Below Amortized Cost, Fair Value	1,468	2,101
More Than Twelve Months Below Amortized Cost, Unrealized Capital Losses	157	124
Total, Fair Value	1,958	2,290
Total, Unrealized Capital Losses	169	129
Residential mortgage-backed securities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Twelve Months or Less Below Amortized Cost, Fair Value	311	114
Twelve Months or Less Below Amortized Cost, Unrealized Capital Losses	8	3
More Than Twelve Months Below Amortized Cost, Fair Value	1,210	1,354
More Than Twelve Months Below Amortized Cost, Unrealized Capital Losses	253	254
Total, Fair Value	1,521	1,468
Total, Unrealized Capital Losses	261	257
Commercial mortgage-backed securities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Twelve Months or Less Below Amortized Cost, Fair Value	24	84
Twelve Months or Less Below Amortized Cost, Unrealized Capital Losses	0	2
More Than Twelve Months Below Amortized Cost, Fair Value	2,751	3,269
More Than Twelve Months Below Amortized Cost, Unrealized Capital Losses	532	642
Total, Fair Value	2,775	3,353
Total, Unrealized Capital Losses	532	644
Other asset-backed securities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Twelve Months or Less Below Amortized Cost, Fair Value	93	136
Twelve Months or Less Below Amortized Cost, Unrealized Capital Losses	2	3
More Than Twelve Months Below Amortized Cost, Fair Value	315	1,156
More Than Twelve Months Below Amortized Cost, Unrealized Capital Losses	43	68
Total, Fair Value	408	1,292
Total, Unrealized Capital Losses	$ 45	$ 71