Variable Interest Entities - Summary of the Impact of Qualifying LIHTC Investments (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Low income housing tax credits
Variable Interest Entity [Line Items]
Amortization of qualifying LIHTC investments	$ 9	$ 6	$ 17	$ 11
Low income housing tax credits and other tax benefits related to qualifying LIHTC investments	(8)	(5)	(17)	(9)
Other tax benefits related to qualifying LIHTC investments
Variable Interest Entity [Line Items]
Low income housing tax credits and other tax benefits related to qualifying LIHTC investments	$ (3)	$ (3)	$ (5)	$ (5)

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
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=116633289&loc=SL49122993-202985

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=116633289&loc=SL49122993-202985

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