Investments (Assets Supporting Experience-Rated Contractholder Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Assets Supporting Experience-Rated Contractholder Liabilities [Line Items]
Assets supporting experience-rated contractholder liabilities, at amortized cost or cost	$ 3,249	$ 3,129
Assets supporting experience-rated contractholder liabilities, at fair value	4,781	4,842
Fixed maturities
Assets Supporting Experience-Rated Contractholder Liabilities [Line Items]
Assets supporting experience-rated contractholder liabilities, at amortized cost or cost	922	895
Assets supporting experience-rated contractholder liabilities, at fair value	915	896
Equity securities
Assets Supporting Experience-Rated Contractholder Liabilities [Line Items]
Assets supporting experience-rated contractholder liabilities, at amortized cost or cost	2,327	2,234
Assets supporting experience-rated contractholder liabilities, at fair value	3,866	3,946
Corporate securities
Assets Supporting Experience-Rated Contractholder Liabilities [Line Items]
Assets supporting experience-rated contractholder liabilities, at amortized cost or cost	60	57
Assets supporting experience-rated contractholder liabilities, at fair value	57	55
Foreign government securities
Assets Supporting Experience-Rated Contractholder Liabilities [Line Items]
Assets supporting experience-rated contractholder liabilities, at amortized cost or cost	633	611
Assets supporting experience-rated contractholder liabilities, at fair value	612	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	229	227
Assets supporting experience-rated contractholder liabilities, at fair value	$ 246	$ 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	99.00%	99.00%