Variable Interest Entities - Investments in Qualified Affordable Housing Tax Credits (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
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	38	62	125	94
Tax credits and other benefits	$ (47)	$ (74)	$ (148)	$ (111)

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

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Amount of amortization expense of investment in qualified affordable housing projects.

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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.

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