Debt and Credit Facilities (Long-Term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Long-term debt, gross	$ 4,396	$ 3,407
Other long-term debt	29	36
Adjustments for unamortized gains on interest rate swap terminations	(6)	(7)
Less: current portion	(4)	(4)
Long-term debt	$ 4,386	3,396
2% Senior Convertible Notes due 2020
Debt Instrument [Line Items]
Debt instrument stated interest rate (percent)	2.00%
Long-term debt, gross	$ 993	$ 0
3.5% senior notes due 2021
Debt Instrument [Line Items]
Debt instrument stated interest rate (percent)	3.50%	3.50%
Long-term debt, gross	$ 396	$ 395
3.75% senior notes due 2022
Debt Instrument [Line Items]
Debt instrument stated interest rate (percent)	3.75%	3.75%
Long-term debt, gross	$ 748	$ 748
3.5% senior notes due 2023
Debt Instrument [Line Items]
Debt instrument stated interest rate (percent)	3.50%	3.50%
Long-term debt, gross	$ 595	$ 594
4.0% senior notes due 2024
Debt Instrument [Line Items]
Debt instrument stated interest rate (percent)	4.00%	4.00%
Long-term debt, gross	$ 590	$ 589
6.5% debentures due 2025
Debt Instrument [Line Items]
Debt instrument stated interest rate (percent)	6.50%	6.50%
Long-term debt, gross	$ 118	$ 118
7.5% debentures due 2025
Debt Instrument [Line Items]
Debt instrument stated interest rate (percent)	7.50%	7.50%
Long-term debt, gross	$ 346	$ 346
6.5% debentures due 2028
Debt Instrument [Line Items]
Debt instrument stated interest rate (percent)	6.50%	6.50%
Long-term debt, gross	$ 36	$ 36
6.625% senior notes due 2037
Debt Instrument [Line Items]
Debt instrument stated interest rate (percent)	6.625%	6.625%
Long-term debt, gross	$ 54	$ 54
5.5% senior notes due 2044
Debt Instrument [Line Items]
Debt instrument stated interest rate (percent)	5.50%	5.50%
Long-term debt, gross	$ 400	$ 400
5.22% debentures due 2097
Debt Instrument [Line Items]
Debt instrument stated interest rate (percent)	5.22%	5.22%
Long-term debt, gross	$ 91	$ 91

Unamortized Gain on Interest Rate Swap Termination

No definition available.

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

- Definition

Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer.

+ 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 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 20
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 16
-Article 9

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Amount of long-term debt, after unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

+ Details

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

- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

+ Details

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

- Definition

Including both current and noncurrent portions, carrying amount as of the balance sheet date of other forms of debt not elsewhere specified in the taxonomy with initial maturities beyond one year or beyond the normal operating cycle, if longer.

+ References

+ Details

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

- Details

Name:	us-gaap_LongtermDebtTypeAxis=msi_TwoPercentSeniorConvertibleNotesDueTwentyTwentyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=msi_ThreePointFivePercentSeniorNotesDueTwentyTwentyOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=msi_ThreePointSevenFivePercentSeniorNotesDueTwoThousandTwentyTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=msi_ThreePointFiveZeroZeroPercentSeniorNotesDue2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=msi_FourPointZeroPercentSeniorNoteDueTwentyTwentyFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=msi_SixPointFivePercentDebenturesDueTwoThousandTwentyFiveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=msi_SevenPointFivePercentDebenturesDueTwoThousandTwentyFiveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=msi_SixPointFivePercentDebenturesDueTwoThousandTwentyEightMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=msi_SixPointSixTwoFivePercentSeniorNotesDueTwoThousandThirtySevenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=msi_FivePointFivePercentSeniorNotesDueTwoThousandFortyFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=msi_FivePointTwoTwoPercentDebenturesDueTwoThousandNinetySevenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: