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Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

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Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

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Employee Retirement Benefits (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Aug. 31, 2008
Defined Benefit Plans and Other Postretirement Benefit Plans
Minimum participant age to elect				40 years
Employer discretionary contribution amount	$ 29	$ 26	$ 24
Requisite service period	3 years
Actual percentage return on plan assets	18.70%	11.80%
Pension plan assets at fair value	$ 358	$ 317	332
Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans
Matching contribution to defined contribution plan	6.00%
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans
Percentage of increase decrease in benefit obligations discount rate	0.64%
Change In Net Benefit Cost Discount Rate Assumption	0.30%
Pension Plan \| Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans
Cash dividends paid (less than $1 million)	$ 1	1
Supplemental Employee Retirement Plan
Defined Benefit Plans and Other Postretirement Benefit Plans
Accrued employee benefit	$ 13	11
Percentage of increase decrease in benefit obligations discount rate	0.55%
Change In Net Benefit Cost Discount Rate Assumption	0.31%
Expected contribution by employer during 2023	$ 8
Top Hat Savings Plan - Mutual Funds and Common Equities
Defined Benefit Plans and Other Postretirement Benefit Plans
CFC Top Hat Savings Plan	87	67
Top Hat
Defined Benefit Plans and Other Postretirement Benefit Plans
CFC Top Hat Savings Plan	87	67
Top Hat \| Top Hat Savings Plan - Mutual Funds and Common Equities \| Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans
Employer discretionary contribution amount	$ 1	$ 1	$ 1
Employer Common Stock
Defined Benefit Plans and Other Postretirement Benefit Plans
Pension plan assets, shares	100,610	100,610
Pension plan assets, fair value	$ 14	$ 10
Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	83.00%
Pension plan assets at fair value	$ 297	269
Equity Securities \| Information Technology Sector
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	31.00%
Equity Securities \| Financial Services Sector
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	20.00%
Equity Securities \| Industrial Sector
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	17.00%
Equity Securities \| Healthcare Sector
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	12.00%
Equity Securities \| All Remaining Sectors
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	10.00%
Fixed Maturities
Defined Benefit Plans and Other Postretirement Benefit Plans
Pension plan assets at fair value	$ 25	32
Fixed Maturities \| United States Government
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	4.00%
Pension plan assets at fair value	$ 13	22
Fixed Maturities \| States, Municipalities and Political Subdivisions
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	2.00%
Pension plan assets at fair value	$ 5	6
Fixed Maturities \| Domestic Corporate Debt Securities
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	1.00%
Pension plan assets at fair value	$ 7	4
Cash and Cash Equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	10.00%
Pension plan assets at fair value	$ 36	$ 16