Income Taxes (Components Of Deferred Tax Assets And Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Inventory	$ 34us-gaap_DeferredTaxAssetsInventory	$ 46us-gaap_DeferredTaxAssetsInventory
Accrued liabilities and allowances	148	129
Employee benefits	799	814
Capitalized items	379	144
Tax basis differences on investments	(10)msi_TaxBasisDifferencesOnInvestments	17msi_TaxBasisDifferencesOnInvestments
Depreciation tax basis differences on fixed assets	52	12
Undistributed non-U.S. earnings	(18)	(6)
Tax carryforwards	1,246	1,294
Business reorganization	22	39
Warranty and customer liabilities	19	19
Deferred revenue and costs	136us-gaap_DeferredTaxAssetsDeferredIncome	159us-gaap_DeferredTaxAssetsDeferredIncome
Valuation allowances	(226)	(200)
Deferred charges	39	38
Other	(38)us-gaap_DeferredTaxLiabilitiesOther	(64)us-gaap_DeferredTaxLiabilitiesOther
Deferred tax assets (liabilities), total	$ 2,582us-gaap_DeferredTaxAssetsLiabilitiesNet	$ 2,441us-gaap_DeferredTaxAssetsLiabilitiesNet

Depreciation Tax Basis Differences On Fixed Assets

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Tax Basis Differences On Investments

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from deferred income.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from inventory.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from property, plant, and equipment.

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The tax effect as of the balance sheet date of the amount of the estimated future tax deductions arising from employee benefit costs not otherwise specified in the taxonomy, which can only be deducted for tax purposes when actual costs are incurred, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the deduction to be taken.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from accrued liabilities.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from other reserves and accruals not separately disclosed.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from other reserves not separately disclosed.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from restructuring reserve.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount of deferred tax liability attributable to taxable temporary differences not separately disclosed.

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Amount of deferred tax liability attributable to taxable temporary differences from undistributed earnings of subsidiaries and other recognized entities not within the country of domicile of the entity.

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