Variable Interest Entities - Investments in Qualified Affordable Housing Tax Credits (Details) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Affordable Housing Investments
Variable Interest Entity [Line Items]
Impairment losses	$ 0	$ 0	$ 0	$ 0
Applicable income tax expense
Variable Interest Entity [Line Items]
Proportional amortization	27,000,000	37,000,000	32,000,000	74,000,000
Tax credits and other benefits	$ (32,000,000)	$ (44,000,000)	$ (37,000,000)	$ (87,000,000)

Amount of affordable housing tax credits and other tax benefits recognized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
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Amount of amortization expense of investment in qualified affordable housing projects.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
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