Investments (Assets Supporting Experience-Rated Contractholder Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Assets Supporting Experience-Rated Contractholder Liabilities [Line Items]
Assets supporting experience-rated contractholder liabilities, at amortized cost or cost	$ 3,280	$ 3,129
Assets supporting experience-rated contractholder liabilities, at fair value	5,405	4,842
Fixed maturities
Assets Supporting Experience-Rated Contractholder Liabilities [Line Items]
Assets supporting experience-rated contractholder liabilities, at amortized cost or cost	908	895
Assets supporting experience-rated contractholder liabilities, at fair value	906	896
Equity securities
Assets Supporting Experience-Rated Contractholder Liabilities [Line Items]
Assets supporting experience-rated contractholder liabilities, at amortized cost or cost	2,372	2,234
Assets supporting experience-rated contractholder liabilities, at fair value	4,499	3,946
Corporate securities
Assets Supporting Experience-Rated Contractholder Liabilities [Line Items]
Assets supporting experience-rated contractholder liabilities, at amortized cost or cost	61	57
Assets supporting experience-rated contractholder liabilities, at fair value	58	55
Foreign government securities
Assets Supporting Experience-Rated Contractholder Liabilities [Line Items]
Assets supporting experience-rated contractholder liabilities, at amortized cost or cost	614	611
Assets supporting experience-rated contractholder liabilities, at fair value	597	596
Obligations of U.S. government authorities and agencies and obligations of U.S. states
Assets Supporting Experience-Rated Contractholder Liabilities [Line Items]
Assets supporting experience-rated contractholder liabilities, at amortized cost or cost	233	227
Assets supporting experience-rated contractholder liabilities, at fair value	$ 251	$ 245
NAIC High or Highest Quality Rating
Assets Supporting Experience-Rated Contractholder Liabilities [Line Items]
Assets supporting experience-rated contractholder liabilities, at amortized cost percentage	100.00%	99.00%