Investments Investments - Rollforward of credit loss allowance for bank loans (Details) - Bank loans, net - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2020
Debt and Equity Securities, FV-NI [Line Items]
Beginning balance	$ (79)	$ 0
Net increases related to credit losses	(3)	(30)
Reduction of allowance related to sales	1	2
Write-offs	5	5
Ending balance	$ (76)	(76)
Cumulative effect of change in accounting principle
Debt and Equity Securities, FV-NI [Line Items]
Beginning balance		$ (53)

Finance Receivables, Allowance for Credit Loss, Securities Sold

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- Definition

Amount, after recovery, of writeoff of financing receivable, charged against allowance for credit loss.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
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- Definition

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

+ References

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-Name Accounting Standards Codification
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- Definition

Amount of increase (decrease) in allowance for credit loss on financing receivable.

+ References

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- Definition

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.

+ References

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