Investments (Mortgage Loans by Portfolio Segment) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Gross	$ 80,635	$ 75,795
Valuation allowances	353	342	$ 314	$ 304
Subtotal mortgage loans, net	80,282	75,453
Mortgage Loans on Real Estate, Commercial and Consumer, Net	80,529	75,752
Total mortgage loans held-for-investment, net	80,470	75,752
Loans Receivable Held-for-sale, Amount	$ 59	$ 0
Percentage Of mortgage total recorded investment To Mortgage Loans On Real Estate Commercial And Consumer Net	100.10%	100.10%
Percentage Of Valuation Allowance To Mortgage Loans On Real Estate Commercial And Consumer Net	(0.40%)	(0.50%)
Percentage Of Mortgage Loans Held For Investment Net To Mortgage Loans On Real Estate Commercial And Consumer Net	99.70%	99.60%
Percentage Of Loans And Leases Receivable Consumer Other To Mortgage Loans On Real Estate Commercial And Consumer Net	0.20%	0.40%
Percentage of total mortgage loans held-for-investments	99.90%	100.00%
Percentage of mortgage loans held-for-sale	0.10%	0.00%
Percentage Of Mortgage Loans On Real Estate To Mortgage Loans On Real Estate Commercial And Consumer Net	100.00%	100.00%
Residential mortgage loans - FVO
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans on Real Estate, Commercial and Consumer, Net	$ 188	$ 299
Commercial Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Gross	49,624	48,463
Valuation allowances	$ 246	$ 238	214	202
Percentage Of Mortgage Loans, Gross	61.60%	64.00%
Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Gross	$ 14,316	$ 12,427
Valuation allowances	$ 55	$ 58	59	63
Percentage Of Mortgage Loans, Gross	17.80%	16.40%
Agricultural Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Gross	$ 16,695	$ 14,905
Valuation allowances	$ 52	$ 46	$ 41	$ 39
Percentage Of Mortgage Loans, Gross	20.70%	19.70%

Percentage of Allowance For Loan And Lease Losses on Real Estate to total Mortgage Loans on Real Estate.

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Percentage Of Financing Receivable, Gross

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Percentage of loans and leases receivable consumer other to total mortgage loans on real estate.

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Percentage of Mortgage Loans Held-for-investment, net to total Mortgage Loans on Real Estate.

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Percentage of Mortgage Loans Held For Investment to total Mortgage Loans on Real Estate.

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Percentage of Mortgage Loans On Real Estate to total Mortgage Loans on Real Estate.

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Percentage of mortgage loans held-for-sale

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Percentage of total mortgage loans held-for-investments

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The reserve to cover probable credit losses related to specifically identified fixed maturity real estate loans as well as probable credit losses inherent in the remainder of that loan portfolio.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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The face amount of loans that will be sold to other entities.

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The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

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Amount, before allowance for credit loss, of financing receivable.

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Amount, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement.

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