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=120269885&loc=SL75117546-209714

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Sum of the carrying amounts as of the balance sheet date of all investments.

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-SubTopic 210
-Section S99
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Investments - Other Segments and Holding Company (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Schedule of Investments [Line Items]
Investments	$ 9,897		$ 9,897		$ 8,913
Other Segments and Holding Company
Schedule of Investments [Line Items]
Investments	244		244		674
Unrealized gains (losses) that relate to equity securities still held	(86)	$ (93)	(42)	$ (259)
Other Segments and Holding Company \| Equity method investments
Schedule of Investments [Line Items]
Investments	91		91		120
Other Segments and Holding Company \| Held to maturity debt investments measured at amortized cost
Schedule of Investments [Line Items]
Investments					20
Other Segments and Holding Company \| Other investments (measured at fair value)
Schedule of Investments [Line Items]
Investments	$ 153		$ 153		$ 534