Commitments and Contingencies - Summary (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Investments in affordable housing projects:
Carrying amount	$ 2,068	$ 1,948
Amount of future funding commitments included in carrying amount	947	928
Lending exposure	541	561
Tax credits subject to recapture	478	471
Private equity investments	463	471
Future funding commitments to private equity investments	$ 128	$ 143

Future funding commitments to consolidated private equity funds

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- Definition

Outstanding loan commitments to affordable housing investments

+ References

No definition available.

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- Definition

Tax Credits Subject To Recapture Related To Affordable Housing Projects

+ References

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- Definition

Amount 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 (b)
-URI http://asc.fasb.org/extlink&oid=114775393&loc=SL49122993-202985

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- References

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- Definition

Amount of commitment or contingent commitments to qualified affordable housing project investments.

+ 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 (e)
-URI http://asc.fasb.org/extlink&oid=114775393&loc=SL49122993-202985

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- Definition

Aggregate carrying value of owned private equity or other securities for which a quoted market price is not readily determinable, the value of which has been determined by management based upon fair value methods, including pricing of similar securities and valuation techniques and is included in the schedule of financial condition or the balance sheet.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

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