Goodwill and Specifically Identifiable Intangible Assets - Schedule of Intangible Assets by Reportable Segment (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization	$ 228	$ 192
Intangible Assets, Net
Gross Carrying Amount	712	712
Accumulated Amortization	228	192
Life Insurance
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	100	100
Accumulated Amortization	71	67
Intangible Assets, Net
Accumulated Amortization	71	67
Group Protection | VOCRA
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	576	576
Accumulated Amortization	145	115
Intangible Assets, Net
Accumulated Amortization	145	115
Group Protection | VODA
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	31	31
Accumulated Amortization	12	10
Intangible Assets, Net
Accumulated Amortization	12	10
Retirement Plan Services
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	$ 5	$ 5