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Regulatory Matters - Narrative (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Sep. 30, 2017	Dec. 31, 2005	Jun. 30, 2003	Dec. 31, 2018	Dec. 31, 2017
Regulatory Capital Requirements [Abstract]
Proceeds from (repurchase of) trust preferred securities	$ (8)	$ 18	$ 18	$ 10	$ 10
Tier 1 common equity, adequately capitalized ratio, conservation buffer				2.50%

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- Definition

Tier One Common Equity Capital Required for Capital Adequacy to Risk Based Assets, Conservation Buffer

+ References

No definition available.

+ Details

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- Definition

The cash inflow from issuance of trust preferred securities, net of the cash outflow for repurchasing trust preferred securities, by a business trust or other special purpose entity, mainly established by a bank holding entity, to third party investors. The trust's assets are deeply subordinated debentures of the bank holding entity. Most trust preferred securities are subject to a mandatory redemption upon the repayment of the debentures.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

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- References

No definition available.

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