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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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Employee Retirement Benefits (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2008
Defined Benefit Plans and Other Postretirement Benefit Plans
Minimum participant age to elect				40 years
Employer discretionary contribution amount	$ 22	$ 22	$ 19
Requisite service period	3 years
Actual return on plan assets	24.50%	11.40%
Pension plan assets at fair value	$ 397	$ 357	354
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	0.29%
Change In Net Benefit Cost Discount Rate Assumption	0.72%
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	$ 9	10
Percentage of increase decrease in benefit obligations discount rate	0.38%
Change In Net Benefit Cost Discount Rate Assumption	0.81%
Expected contribution by employer during 2021	$ 6
Top Hat Savings Plan - Mutual Funds and Common Equities
Defined Benefit Plans and Other Postretirement Benefit Plans
CFC Top Hat Savings Plan	64	51
Top Hat \| Top Hat Savings Plan - Mutual Funds and Common Equities
Defined Benefit Plans and Other Postretirement Benefit Plans
CFC Top Hat Savings Plan	64	51
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
Defined Benefit Plan, Equity Securities, Common Stock, Employer, Related Party
Defined Benefit Plans and Other Postretirement Benefit Plans
Pension plan assets, shares	202,337	202,337
Pension plan assets, fair value	$ 23	$ 18
Defined Benefit Plan, Equity Securities, Common Stock, Employer, Related Party \| Employee Stock
Defined Benefit Plans and Other Postretirement Benefit Plans
Pension plan assets, shares		29,776
Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	87.00%
Pension plan assets at fair value	$ 332	$ 266
Equity Securities \| Information Technology Sector
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	32.00%
Equity Securities \| Financial Services Sector
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	20.00%
Equity Securities \| Healthcare Sector
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	13.00%
Equity Securities \| Industrial 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	$ 49	60
Fixed Maturities \| United States Government
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	8.00%
Pension plan assets at fair value	$ 31	31
Fixed Maturities \| Domestic Corporate Debt Securities
Defined Benefit Plans and Other Postretirement Benefit Plans
Allocation percentage of investments	3.00%
Pension plan assets at fair value	$ 11	20
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	$ 7	9
Cash and Cash Equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans
Pension plan assets at fair value	$ 16	$ 31