Business Combination, Customary Adjustment, Primarily Related to Working Capital

No definition available.

Name:	bgc_BusinessCombinationCustomaryAdjustmentPrimarilyRelatedToWorkingCapital
Namespace Prefix:	bgc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Business Combination, Interest Acquired

+ References

No definition available.

+ Details

Name:	bgc_BusinessCombinationInterestAcquired
Namespace Prefix:	bgc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of Manufacturing Locations Acquired

+ References

No definition available.

+ Details

Name:	bgc_NumberofManufacturingLocationsAcquired
Namespace Prefix:	bgc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Period for Purchasing of Minority Shareholders'

+ References

No definition available.

+ Details

Name:	bgc_PeriodforPurchasingofMinorityShareholders
Namespace Prefix:	bgc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Proceeds Used for Extinguishment of Debt

+ References

No definition available.

+ Details

Name:	bgc_ProceedsUsedforExtinguishmentofDebt
Namespace Prefix:	bgc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Subscription of Outstanding and Issued Shares, Percent

+ References

No definition available.

+ Details

Name:	bgc_SubscriptionofOutstandingandIssuedSharesPercent
Namespace Prefix:	bgc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of persons employed by the Entity

+ References

No definition available.

+ Details

Name:	dei_EntityNumberOfEmployees
Namespace Prefix:	dei_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Definition

Amount recognized as of the acquisition date for the assets, including goodwill, in excess of (less than) the aggregate liabilities assumed, less the noncontrolling interest in the acquiree.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=39739317&loc=d3e4845-128472

+ Details

Name:	us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Gross amount of debt extinguished.

+ References

No definition available.

+ Details

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

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireBusinessesGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.4)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 4

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 330

-SubTopic 10

-Section 30

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=34747878&loc=d3e3636-108311

+ Details

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

- Details

Name:	dei_LegalEntityAxis=bgc_ProcablesSAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=bgc_SellerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=bgc_PrestoliteWireLlcPrestoliteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=bgc_ProcablesSAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=country_CN
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_NorthAmericaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Acquisitions and Divestitures (Narrative) (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	12 Months Ended			0 Months Ended
	Oct. 01, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Nov. 02, 2012 Facilities employees	Dec. 03, 2012 employees	Sep. 04, 2012
Business Acquisition [Line Items]
Selling, general and administrative expenses		$ 450.7	$ 492.0	$ 425.5
Subscription of outstanding and issued shares, percent	60.00%
Business combination, interest acquired	27.4bgc_BusinessCombinationInterestAcquired
Period for purchasing of minority shareholders'	36 months
ProCables S.A. [Member]
Business Acquisition [Line Items]
Subscription of outstanding and issued shares, percent	60.00%
ProCables S.A. [Member] \| Latin America [Member]
Business Acquisition [Line Items]
Cost of acquired entity, purchase price	18.3
Selling, general and administrative expenses	0.6
ProCables S.A. [Member] \| Latin America [Member] \| Minimum [Member]
Business Acquisition [Line Items]
Number of employees	500
Prestolite [Member]
Business Acquisition [Line Items]
Cost of acquired entity, purchase price					59.5
Selling, general and administrative expenses					0.6
Number of employees					700
Number of manufacturing locations acquired					2
CHINA [Member] \| Alcan Cable [Member]
Business Acquisition [Line Items]
Cost of acquired entity, purchase price						57.7
Selling, general and administrative expenses						1.1
Number of employees						300
North America [Member] \| Alcan Cable [Member]
Business Acquisition [Line Items]
Cost of acquired entity, purchase price							151.0
Customary adjustment, primarily related to working capital							20.3
Cash paid for acquired entity							171.3
Selling, general and administrative expenses							3.3
North America [Member] \| Alcan Cable [Member] \| Minimum [Member]
Business Acquisition [Line Items]
Number of employees							750
Seller [Member]
Business Acquisition [Line Items]
Noncontrolling interest, ownership percentage by parent	40.00%
ProCables S.A. [Member]
Business Acquisition [Line Items]
Proceeds used for extinguishment of debt	24.0
Extinguishment of debt	$ 48.1