Name:	cyn_DistributionsToRedeemableNoncontrollingInterestHolders
Namespace Prefix:	cyn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Represents the number of consolidated investment advisory affiliates.

No definition available.

Name:	cyn_NumberOfConsolidatedInvestmentAdvisoryAffiliates
Namespace Prefix:	cyn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the number of real estate investment trust subsidiaries of the entity.

No definition available.

Name:	cyn_NumberOfRealEstateInvestmentSubsidiaries
Namespace Prefix:	cyn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the net increase or decrease in redeemable noncontrolling interest from such activities as the issuance of additional equity interests to noncontrolling interest holders, the sale of a portion of the parent's controlling interest, redeeming or purchasing the interests of noncontrolling shareholders, issuance of shares by the non-wholly owned subsidiary to the parent entity, and buyback of shares by the non-wholly owned subsidiary from the noncontrolling interests.

No definition available.

Name:	cyn_RedeemableNoncontrollingInterestIncreaseDecreaseNet
Namespace Prefix:	cyn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents adjustments to redeemable noncontrolling interest not otherwise specified in the taxonomy.

No definition available.

Name:	cyn_RedeemableNoncontrollingInterestOtherAdjustments
Namespace Prefix:	cyn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Change in the redeemable noncontrolling interest during the period as a result of a change in the fair value of redeemable noncontrolling interest.

No definition available.

Name:	cyn_RedeemableNoncontrollingInterestsFairValueAdjustment
Namespace Prefix:	cyn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_MovementInMinorityInterestRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The portion of net income or loss for the period attributable to redeemable noncontrolling interest (if any) deducted in order to derive the portion attributable to the parent. This element should be used for redeemable noncontrolling interests that are classified within temporary equity.

No definition available.

Name:	us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_NoncontrollingInterestAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The aggregate fair value as of the reporting date of all noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. This item includes noncontrolling interest holder's ownership (or holders' ownership) regardless of the type of equity interest (common, preferred, other) including all potential organizational (legal) forms of the investee entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 480

-SubTopic 10

-Subparagraph (12)(c)

-Section S99

-Paragraph 3A

-URI http://asc.fasb.org/extlink&oid=6802392&loc=SL6540498-122764

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 480

-SubTopic 10

-Subparagraph 14

-Paragraph 3A

-Section S99

-URI http://asc.fasb.org/extlink&oid=6802392&loc=SL6540498-122764

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number D-98

-Paragraph 43

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 480

-SubTopic 10

-Subparagraph 15

-Paragraph 3A

-Section S99

-URI http://asc.fasb.org/extlink&oid=6802392&loc=SL6540498-122764

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number D-98

-Paragraph 43

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph 27

-Appendix A

-Subparagraph c

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 480

-SubTopic 10

-Subparagraph (16)(c)

-Paragraph 3A

-Section S99

-URI http://asc.fasb.org/extlink&oid=6802392&loc=SL6540498-122764