Other Financial Data (Other Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Other Liabilities [Abstract]
Defined benefit plans	$ 1,611	$ 1,751
Postretirement health care benefit plan	49	117
Deferred revenue	139us-gaap_DeferredRevenueNoncurrent	162us-gaap_DeferredRevenueNoncurrent
Unrecognized tax benefits	54msi_UnrecognizedTaxBenefitsNoncurrent	99msi_UnrecognizedTaxBenefitsNoncurrent
Other	158	185
Other liabilities	$ 2,011us-gaap_OtherLiabilitiesNoncurrent	$ 2,314us-gaap_OtherLiabilitiesNoncurrent

This element represents other noncurrent liabilities other than specified in the taxonomy.

No definition available.

Name:	msi_OtherUnspecifiedNoncurrentLiabilities
Namespace Prefix:	msi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The non-current portion of the gross amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns as of the balance sheet date, excluding amounts pertaining to examined tax returns.

+ References

No definition available.

+ Details

Name:	msi_UnrecognizedTaxBenefitsNoncurrent
Namespace Prefix:	msi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The noncurrent portion of deferred revenue amount as of balance sheet date. Deferred revenue is a liability related to a revenue producing activity for which revenue has not yet been recognized, and is not expected to be recognized in the next twelve months. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 13.A.4(a).Q1)

-URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 8

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6935-107765

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 13

-Section A

+ Details

Name:	us-gaap_DeferredRevenueNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This represents the noncurrent liability recognized in the balance sheet that is associated with the defined benefit pension plans.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.24)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e2417-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e2410-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=21915240&loc=d3e1703-114919

+ Details

Name:	us-gaap_DefinedBenefitPensionPlanLiabilitiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Aggregate carrying amount, as of the balance sheet date, of noncurrent obligations not separately disclosed in the balance sheet. Noncurrent liabilities are expected to be paid after one year (or the normal operating cycle, if longer).

+ References

+ Details

Name:	us-gaap_OtherLiabilitiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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

- Definition

This represents the noncurrent liability recognized in the balance sheet that is associated with other postretirement defined benefit plans (excluding pension plans).

+ References

+ Details

Name:	us-gaap_OtherPostretirementDefinedBenefitPlanLiabilitiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant