Investments - Components of Net Investment Income (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net Investment Income [Line Items]
Investment income	$ 1,608	$ 1,296	$ 1,443
Less investment expenses	59	52	53
Net investment income	1,549	1,244	1,390
Debt securities
Net Investment Income [Line Items]
Investment income	689	962	986
Equity securities
Net Investment Income [Line Items]
Investment income	12	11	5
Commercial mortgage loans
Net Investment Income [Line Items]
Investment income	60	80	88
Policy loans
Net Investment Income [Line Items]
Investment income	63	64	66
Other long-term investments
Net Investment Income [Line Items]
Investment income	758	127	167
Short-term investments and cash
Net Investment Income [Line Items]
Investment income	$ 26	$ 52	$ 131

Represents the total of interest and dividend income, including any amortization and accretion (as applicable) of discounts and premiums, earned from (1) loans and leases whether held-for-sale or held-in-portfolio; (2) investment securities; (3) federal funds sold; (4) securities purchased under agreements to resell; (5) investments in banker's acceptances, commercial paper, or certificates of deposit; (6) dividend income; or (7) other investments not otherwise specified herein. Also includes the total amount of revenue recognized for the period from operating leases, including minimum lease revenue, contingent revenue, percentage revenue and sublease revenue.

No definition available.

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Amount of expenses related to the generation of investment income.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
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-Section S99
-Paragraph 2
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Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(2))
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