Fair Value Measurements Level 4 Financial Instruments Not Carried At Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	$ 158,888	$ 154,713
Assets, Fair Value Disclosure	124,509	116,376
Liabilities	155,703	152,161
Financing Receivable, Allowance for Credit Loss	(17)	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, Fair Value Disclosure	878	893
Reported Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member] \| Other Policyholder Funds and Benefits Payable [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	5,282	6,049
Reported Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member] \| Investment Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	0	1
Reported Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member] \| Policy loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	1,452	1,467
Reported Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member] \| Mortgage loans [1]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	2,092	2,241
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member] \| Other Policyholder Funds and Benefits Payable [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial Liabilities Fair Value Disclosure	5,261	5,912
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member] \| Investment Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial Liabilities Fair Value Disclosure	0	1
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member] \| Policy loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, Fair Value Disclosure	1,452	1,467
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member] \| Mortgage loans [1]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, Fair Value Disclosure	$ 2,248	$ 2,331

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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

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Sum of the carrying amounts as of the balance sheet date of all liabilities that are recognized. Liabilities are probable future sacrifices of economic benefits arising from present obligations of an entity to transfer assets or provide services to other entities in the future.

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