Investments (Net Investment Income) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net Investment Income [Line Items]
Less: Investment expenses	$ 232	$ 238	$ 701	$ 798
Net investment income	5,568	4,729	16,162	11,877
Securities Investment
Net Investment Income [Line Items]
Gross Investment Income, Operating	5,686	4,705	16,164	12,735
Net investment income	5,454	4,467	15,463	11,937
Fixed Maturity Securities
Net Investment Income [Line Items]
Gross Investment Income, Operating	2,759	2,820	8,251	8,482
Equity Securities
Net Investment Income [Line Items]
Gross Investment Income, Operating	8	15	28	40
Equity Securities, FV-NI, Unrealized Gain (Loss)	(16)	(2)	86	(198)
FVO Securities (1)
Net Investment Income [Line Items]
Gross Investment Income, Operating	6	36	92	72
Mortgage loans
Net Investment Income [Line Items]
Gross Investment Income, Operating	838	885	2,586	2,631
Policy loans
Net Investment Income [Line Items]
Gross Investment Income, Operating	118	124	359	374
Real Estate and Real Estate Joint Ventures
Net Investment Income [Line Items]
Gross Investment Income, Operating	279	104	660	371
Other limited partnership interests
Net Investment Income [Line Items]
Net investment income	1,541	578	3,870	291
Cash, cash equivalents and short-term investments
Net Investment Income [Line Items]
Gross Investment Income, Operating	25	40	74	184
Operating joint ventures
Net Investment Income [Line Items]
Gross Investment Income, Operating	17	25	55	81
Other Investments
Net Investment Income [Line Items]
Gross Investment Income, Operating	95	78	189	209
Unit-linked investments
Net Investment Income [Line Items]
Net investment income	114	262	699	(60)
Equity Securities, FV-NI, Unrealized Gain (Loss)	$ 55	$ 240	$ 577	$ (83)

Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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(3)(d))
-URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=123583765&loc=SL75117546-209714

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Amount, before 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.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Section S99
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