Intangible Assets and Goodwill (Goodwill) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]
Aggregate goodwill acquired/disposed	$ 383msi_AggregateGoodwillAcquired	$ 361msi_AggregateGoodwillAcquired	$ 361msi_AggregateGoodwillAcquired
Accumulated impairment losses	0msi_AccumulatedImpairmentLosses	0msi_AccumulatedImpairmentLosses	0msi_AccumulatedImpairmentLosses
Goodwill, net of impairment losses	383us-gaap_Goodwill	361us-gaap_Goodwill	361us-gaap_Goodwill
Goodwill acquired	22us-gaap_GoodwillAcquiredDuringPeriod
Products
Goodwill [Line Items]
Aggregate goodwill acquired/disposed	264	249	249
Accumulated impairment losses	0	0	0
Goodwill, net of impairment losses	264	249	249
Goodwill acquired	15
Services
Goodwill [Line Items]
Aggregate goodwill acquired/disposed	119	112	112
Accumulated impairment losses	0	0	0
Goodwill, net of impairment losses	119	112	112
Goodwill acquired	$ 7

This element represents the accumulated amount of impairment losses as of the balance sheet date.

No definition available.

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

- Definition

This element represents the aggregate amount of goodwill acquired as of the balance sheet date. This goodwill is excluding any effect of impairment losses.

+ References

No definition available.

+ Details

Name:	msi_AggregateGoodwillAcquired
Namespace Prefix:	msi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

+ Details

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

- Definition

Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

+ Details

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

- Details

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

- Details

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

- Details

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