Reserves for Future Policy Benefits and Contract Owner Account Balances (Details) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($) professional	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	$ 590	$ 385	$ 392
Current Year Claims and Claims Adjustment Expense	1,538	1,042
Prior Year Claims and Claims Adjustment Expense	(143)	(8)
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims	1,681	1,034
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year	(964)	(665)
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years	512	376
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid	(1,476)	(1,041)
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	(5)	(16)	(6)
Liability for Claims and Claims Adjustment Expense	595	401	398
Short-Duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	3,599
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years	512	376
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	590
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	(3,009)
Short-Duration Insurance Contract, Accident Year 2022
Short-Duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	870	872	859
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 2
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | professional	26,060,000,000
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ (868)	(862)	$ (496)
Short-Duration Insurance Contract, Accident Year 2023
Short-Duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,191	1,042
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 14
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | professional	32,515,000,000
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ (1,177)	$ (665)
Short-Duration Insurance Contract, Accident Year 2024
Short-Duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,538
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 574
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | professional	24,560,000,000
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ (964)