Adoption of ASU 2018-12 - Summary of Changes in Net Liability Position of MRBs (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net	$ (2,178)	$ (729)		$ 5,334
Retirement Plan Services
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net				9
Cumulative effect from adoption of new accounting standards | Accounting Standards Update 2018-12 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net				7,956
Cumulative effect from adoption of new accounting standards | Accounting Standards Update 2018-12 | Retained Earnings | Retirement Plan Services
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net				10
As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net				1,034
As Previously Reported | Retirement Plan Services
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net				11
Cumulative Effect of Credit Risk to AOCI | Cumulative effect from adoption of new accounting standards | Accounting Standards Update 2018-12 | AOCI
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net				(3,656)
Cumulative Effect of Credit Risk to AOCI | Cumulative effect from adoption of new accounting standards | Accounting Standards Update 2018-12 | AOCI | Retirement Plan Services
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net				(12)
Variable Annuities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net	(2,180)	(662)	$ 2,398	5,207
Variable Annuities | Cumulative effect from adoption of new accounting standards
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net		(2,173)	(2,425)
Variable Annuities | Cumulative effect from adoption of new accounting standards | Accounting Standards Update 2018-12 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net				7,968
Variable Annuities | As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net				831
Variable Annuities | Cumulative Effect of Credit Risk to AOCI | Cumulative effect from adoption of new accounting standards | Accounting Standards Update 2018-12 | AOCI
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net				(3,592)
Fixed Annuities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net	$ 32	(45)	114	118
Fixed Annuities | Cumulative effect from adoption of new accounting standards
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net		$ (40)	$ (44)
Fixed Annuities | Cumulative effect from adoption of new accounting standards | Accounting Standards Update 2018-12 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net				(22)
Fixed Annuities | As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net				192
Fixed Annuities | Cumulative Effect of Credit Risk to AOCI | Cumulative effect from adoption of new accounting standards | Accounting Standards Update 2018-12 | AOCI
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
MRBs, net				$ (52)