Future Contract Benefit - Summary of Reconciliation of Future Contract Benefits (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Liability for Future Policy Benefit, Activity [Line Items]
Future contract benefits	$ 38,848	$ 39,864
Other
Liability for Future Policy Benefit, Activity [Line Items]
Future contract benefits	3,322	3,371
Payout Annuities
Liability for Future Policy Benefit, Activity [Line Items]
Future contract benefits	2,034	2,085	$ 2,068
Traditional Life
Liability for Future Policy Benefit, Activity [Line Items]
Future contract benefits	3,793	3,841	$ 3,681
Group Protection
Liability for Future Policy Benefit, Activity [Line Items]
Future contract benefits	5,640	5,689
UL and Other
Liability for Future Policy Benefit, Activity [Line Items]
Future contract benefits	14,444	15,000
Other Operations
Liability for Future Policy Benefit, Activity [Line Items]
Future contract benefits	9,615	9,879
Protective | Other Operations
Liability for Future Policy Benefit, Activity [Line Items]
Future contract benefits	5,500	5,600
Swiss Re | Other Operations
Liability for Future Policy Benefit, Activity [Line Items]
Future contract benefits	$ 2,200	$ 2,200